Category Archives: Research & Trends


New Study Challenges Traditional Procedures Following Police Shootings

A new study has challenged the traditional practice of allowing an officer time to “cool-off” before giving a statement following a police shooting.

Recovery Time Following Shooting

Traditionally, when a police officer is involved in a shooting, the officer is given a period of time to recover before providing his or her statement. The International Association of Chiefs of Police “Officer-Involved Shooting Guidelines” recommends that “Officers should have some recovery time before providing a full formal statement… An officer’s memory will often benefit from at least one sleep cycle prior to being interviewed leading to more coherent and accurate statements.”

This recommended waiting period is mandated by rules or laws in many jurisdictions. Other police departments have agreements with police unions to honor the waiting period. This waiting period is recommended by Bill Lewinski, a behavioral scientist who many police officers believe to be the definitive expert on interviewing officers after shooting. Lewinski is a professor emeritus of Law Enforcement at Minnesota State University and the founder and director of the Force Science Institute, a research, consulting, and training organization focused on human behavior in use-of-force situations.

Lewinski has studied police use-of-force issues since 1975 and has opined that “delay enhances an officer’s ability to more accurately and completely respond to questions.” Lewinski has recommended “a recovery period of at least 48 hours before being interviewed in depth.”

Of course, if delay after a stressful event enhances memory, one might expect the police to delay interrogations of the people they arrest for shootings for 48 hours to give their memories a chance to improve. That isn’t their practice, because the real benefit of delay to a shooter is the opportunity to fabricate a coherent and innocent explanation of the shooting.

New Study by Criminologists

Criminologists Geoff Alpert, Louise Porter, and Justin Ready conducted a study to test the theory that a police officer’s memory will benefit for a cooling-off period. The study involved 87 police officers who participated in a live active-shooter simulation in an abandoned building. The officers were divided into two groups: half were interviewed immediately after the shooting and the other half was interviewed two days later. The first group was also interviewed two days later, to see how their memory performed in a second interview.

The interview process consisted of 19-multiple choice questions related to the shooting. Nine questions were related to the threat and 10 questions were about nonthreatening details. Following the interviews, the researchers concluded that the officers’ cognition “did not seem to be directly affected by how recently they had experienced the scenario, and no significant improvement was evident after two days either between or within groups.”  The researchers noted that the “recall of non-threat related information was significantly better in the immediate condition compared with the delayed condition.”

The researchers concluded that early questioning can aid memory retention. They stated, “We did not find any evidence … that delay improves either recall or cognitive capability that could indicate enhanced ability to respond to questioning.”

Lewiniski criticized the study and its use of multiple-choice questions to evaluate accuracy of memory and stress levels. Lewinski suggested that a more realistic study would involve heart rate and pulse monitors and trained cognitive interviewers. Lewinski also noted that the study did not take into account that many officers have worked long hours before the time of a shooting or post-event interview, which harms cognitive abilities. Notably, Lewinski has not conducted the “improved” studies to determine whether the results would support his theory that delayed interrogation following a stressful event improves memory.

New Mexico

New Mexico Supreme Court Denies Request to Limit Defense Expert’s Access to Evidence

The New Mexico Supreme Court recently denied the state Attorney General’s request to prevent defense experts from using their own facilities and equipment to analyze evidence in a child pornography prosecution. The Attorney General argued that expert witnesses should use the government’s computers and should examine the evidence in government facilities. The case raises troubling questions about the efforts of prosecutors to hinder the work of defense experts whose analysis of evidence may reveal that no law was broken.

Expert testimony is essential in child pornography cases because Congress can only prohibit the possession of pornography involving actual children. It is not unlawful to possess a drawing or painting of a child that is a product of an artist’s imagination. By the same token, it is not unlawful to possess a digitized image of a child who is not real. Discerning the difference between a digitized photograph of a real child and a digitally created image of a child who isn’t real requires careful expert analysis. Hindering experts from performing that analysis risks the conviction of defendants who committed no crime.

Federal Law and Expert Witnesses

Everyone agrees that when child pornography is used as evidence in a criminal case, the evidence should not be distributed to the public. Possession of child pornography, after all, is illegal.

In federal cases, the U.S. Justice Department went a step further by arguing that defense attorneys should not be given copies of the evidence against their clients in child pornography cases because defense lawyers cannot legally possess it. That position made it difficult for defense lawyers to share the evidence with expert witnesses, who sometimes discover that the images seized from defendants do not depict children, or even real people, and that they are not in fact illegal to possess. A cynic might suspect that undermining the ability of defense experts to challenge the prosecution’s evidence is exactly why the Justice Department does not want to share its evidence.

When defense attorneys pointed out that prosecutors were in possession of suspected child pornography and asked why prosecutors could possess it if defense lawyers couldn’t, the answer was typically “Because we’re the government and you’re not.” Courts did not always view that as a sensible answer. Some courts required prosecutors to give copies of the evidence to defense attorneys, so that expert witnesses could examine the images using the equipment in their facilities, subject to protective orders that prevented the release of the evidence to anyone else.

When courts began to give defendants meaningful access to evidence, the Justice Department asked Congress to pass a law making prosecutors the “custodians” of suspected images of child pornography and prohibiting defense attorneys from obtaining copies of those images. The law served no important public policy, since nobody seriously believed that defense attorneys or their experts were violating protective orders by distributing allegedly pornographic images to the public. Many defense attorneys suspected that prosecutors simply wanted to make it harder for defendants to have a fair trial by preventing defense experts from conducting a meaningful analysis of the evidence. As it usually does, however, Congress gave the Justice Department what it wanted.

In other cases, when evidence has been seized from a defendant, federal discovery rules requires the government to give a copy of that evidence to the defense. Congress enacted an exception to that law that applies to child pornography. A federal statute now provides: “(1) In any criminal proceeding, any property or material that constitutes child pornography . . . shall remain in the care, custody, and control of either the Government or the court.” Of course, whether evidence “constitutes child pornography” is exactly the issue that defense experts analyze and that juries must decide, but prosecutors read the law as if it says “any property or material that the government alleges is child pornography.” Courts generally seem to be fine with that interpretation, given that the obvious intent of the federal law is to keep evidence out of the hands of defense attorneys and their experts.

Challenges to Federal Law

Most challenges to the federal law have failed. The law requires prosecutors to give defense attorneys and their experts ample opportunity to examine the evidence at a place chosen by the government, which is usually a conference room in the U.S. Attorney’s office or at the local FBI office. Inspection is usually overseen by a law enforcement agent. Courts have occasionally sided with defense attorneys who argue they were not given sufficient time to analyze the evidence, but courts have not often been receptive to complaints that lawyers should have been given access to the evidence outside the confines of a government office.

Occasionally, however, courts have recognized that expert witnesses cannot conduct a meaningful analysis of the evidence without testing it in the expert’s own facilities. In one case, for example, a computer forensic expert and two digital video experts “described the great cost and effort that would be required to conduct their analyses in a Government facility,” including the expense of moving a large truckload of equipment to the government office and the risk of damaging the equipment during the move. The court sensibly ordered the government to give the expert a mirror image of the defendant’s hard drive so that the experts could analyze it in their own offices.

Notably, prosecutors have sometimes given their own experts unrestricted access to the evidence while limiting the access provided to defense experts. Courts have been appropriately critical of the assumption that private experts hired by the government are more trustworthy than private experts hired by the defense, although federal prosecutors have brazenly argued that private experts somehow become the government when they are hired by the government. At least one court rejected the argument that retained experts are government employees.

New Mexico Court Sides with Defense

The federal law that makes the government the custodian of child pornography evidence only applies to federal prosecutions. A few states have enacted similar laws, but state courts are generally free to safeguard the rights of defendants by entering protective orders when defense attorneys want experts to review the evidence in their own facilities.

Recognizing the important role played by expert witnesses in child pornography cases, a judge in Bernalillo County, New Mexico ordered the prosecution to provide copies of images seized from the defendant to the defense expert. The New Mexico Attorney General asked the state supreme court to reverse the order on the bizarre theory that prosecutors would be violating the law by following the court’s order. The concern that prosecutors will prosecute prosecutors for obeying a judge’s order, an act that clearly immunizes them from prosecution, did not persuade the state supreme court to overturn the judge’s ruling. The court denied the Attorney General’s effort to prevent the defense expert from conducting a fair analysis using the expert’s own equipment.


Missouri Adopts Daubert

To large corporations, insurance companies, and their lobbyists, Missouri is a “judicial hellhole.” To consumers and injury victims, Missouri is a state where business lobbyists have not made it impossible for them to win fair compensation when they are harmed by corporate wrongdoing. Both perspectives are poised to change.

Corporate lobbyists have been fierce advocates for the Daubert rule, which (from their perspective, at least) restricts the admissibility of expert testimony, potentially making it more difficult for plaintiffs to win cases. They realized their dream with the election of Eric Greitens as governor. One of the legislature’s first agenda items was to pass a Daubert bill. Gov. Grietens signed the bill into law in March.

According to Gov. Grietens, Missouri’s adherence to the Frye standard allowed “trial lawyers to come to Missouri, pick our pockets, and hurt our businesses.” The governor cited no example of a verdict against a business that was undeserved. He also failed to identify any “crooked trial lawyers” or “shady witnesses” who affected the outcome of a Missouri trial, although he derided them at the signing ceremony. While the governor’s incendiary language reflects the view of insurance industry lobbyists, it detracts from even the appearance of fair-minded lawmaking.

Again citing no evidence, the governor suggested that the Frye standard “makes us less competitive than other states — at a time when we are fighting for every single job.” Signing the bill, the governor said, sent “a signal to the rest of the country that Missouri is open for business.” Opponents of the bill argued that it sent a message that businesses will no longer be held accountable when their negligent conduct harms consumers.

Daubert in the States

The Daubert standard is named after a United States Supreme Court decision that changed the federal standard for admitting expert testimony. The Daubert standard requires trial judges to act as a gatekeeper to prevent juries from hearing expert testimony unless the expert has applied a reliable methodology in a reliable way to facts that are sufficient to support the expert’s conclusion.

The Missouri legislature’s last attempt to enact a Daubert bill was vetoed by Gov. Jay Nixon, a Democrat. The Florida legislature recently passed a Daubert bill, but the Florida Supreme Court declined to adopt it. A large majority of states have adopted at least part of the Daubert standard, but making a state-by-state comparison is difficult because courts that implement some version of the Daubert rule do not always agree upon its meaning.

Does Daubert Matter?

In a routine case, the standard for expert witness admissibility makes no difference. A treating physician who testifies about the injuries a patient suffered in a car accident will be allowed to give the same testimony regardless of the standard. Daubert hearings in routine cases, however, might drive up the cost of litigation and place an unnecessary burden on overworked judges.

Some lawyers, including some legal scholars, see the Daubert standard as restricting expert testimony by keeping “junk science” out of the courtroom. While Daubert advocates tend to view “junk science” in the context of toxic tort and product liability claims that can only be proved with expert evidence, the Daubert standard has also been used in criminal cases to restrict questionable expert testimony about cellphone location data and the ability to match a bitemark to a suspect.

Other lawyers, including some legal scholars, view Daubert as liberalizing the admissibility of expert testimony. They point out that expert opinions based on new or novel scientific techniques were excluded under the Frye standard because they were not “generally accepted” by the scientific community, but are admissible under Daubert if the new methodology is reliable.

Both of those views have some merit. Daubert both restricts the admissibility of expert evidence by keeping juries from hearing unreliable opinions while opening the door to reliable opinions that are based on new views of science. But in any particular case, how Daubert should be applied is up to the judge, and judges have widely varying views about their gatekeeping role.

Some judges seem to expect experts to express opinions with certainty, which is contrary both to the probabilistic nature of science and to the burden of proof in civil cases. Some judges distrust experts, particularly in civil cases (such as pharmaceutical injury claims) where causation is particularly difficult to prove. Those judges are inclined to resist admitting expert testimony.

Other judges believe it is for the jury, not the judge, to decide whether an expert opinion is trustworthy. Those judges, who tend to recognize that judges are trained in law, not science, are more inclined to admit expert testimony.

Different judges may therefore apply the same Daubert standard to similar facts and arrive at different results. One scholarly analysis concluded that court decisions applying Daubert have been “nonuniform, inconsistent, and irreconcilable.” In the end, notwithstanding the state’s rancorous Daubert debate, how Missouri judges feel about expert evidence may be more important than the standard they apply.

Florida Supreme Court

Florida Supreme Court Rejects Daubert Rule

The Florida Supreme Court has rejected a legislative attempt to impose the Daubert standard of expert witness admissibility on Florida courts. As ExpertPages earlier reported, the Florida Bar’s Board of Governors asked the Florida Supreme Court to set aside a legislative attempt to force the state’s judiciary to use the Daubert standard when deciding whether to admit expert testimony.

The Board of Governors narrowly sided with lawyers who represent injury victims when it asked the Court to reject Daubert. They argued that Daubert benefits corporations and other powerful defendants by restricting the evidence that might be used to prove their wrongdoing. The business and insurance community, on the other hand, contended that Daubert provides a safeguard against the use of “junk science” to sway juries.

The Legislature v. The Court

Florida courts have historically followed the Frye standard to determine the admissibility of expert testimony. As applied in Florida, the Frye standard requires trial judges to exclude expert testimony that is based on a new or novel scientific methodology unless it is grounded in principles that have gained general acceptance in the relevant scientific community.

The Florida legislature passed a law that purported to require Florida courts to follow the Daubert standard of expert witness admissibility. That standard generally requires judges to determine the reliability of expert testimony and to exclude opinions that are not based on the reliable application of a reliable methodology to sufficient facts or data.

While it is the legislature’s responsibility to make law, the Florida Supreme Court considers it the judiciary’s responsibility to craft the procedural rules that govern court proceedings. Since rules of evidence are generally regarded as procedural rules rather than substantive laws, the Florida Supreme Court has the power to decide whether evidentiary rules enacted by the legislature will be followed by the courts, at least to the extent that they are procedural.

Florida Bar Recommendation

The Florida Bar’s Code and Rules of Evidence Committee recommended that the Florida Supreme Court decline to adopt the legislatively enacted Daubert standard. The Committee’s Majority Report noted that the legislature wanted to prohibit “pure opinion testimony” in Florida courts, while Florida courts have long endorsed the admissibility of “pure opinions” from qualified experts.

Florida precedent establishes that “pure opinion testimony,” such as a doctor’s diagnosis or a psychologist’s conclusion that a defendant is not competent to stand trial, does not need to satisfy the Frye standard. “Pure expert opinions” are those that are based on training and experience and that might assist the jury even if other experts might dispute them.

Florida precedent cautions trial courts to “resist the temptation to usurp the jury’s role in evaluating the credibility of experts.” Whether conclusions drawn by experts are credible is a question for juries, not judges, to resolve. The Committee argued that a litigant’s constitutional right to trial by jury would be diminished if judges were to decide in the first instance whether an expert’s conclusions are reliable.

The Committee also raised practical objections to Daubert, noting that the standard places an unreasonable burden on courts and litigants while prompting judges to make inconsistent decisions that are based on their own preferences rather than a consistent rule of law. In the end, however, it was the constitutional concern that carried the day in the Florida Supreme Court.

Florida Supreme Court Rejects Daubert

In a brief opinion, the Florida Supreme Court noted that it typically follows a policy of adopting procedural rules that the state legislature enacts. When the Court has doubts about the constitutionality of a procedural change, however, the Court may decline to adopt it.

The Court noted that the Committee raised “grave constitutional concerns” about the impact that the Daubert rule would have on the right to a jury trial and on access to the courts. For that reason, the Court declined to adopt the legislature’s changes to Florida’s rule regarding expert witness admissibility.

The argument that the Daubert standard is unworkable, that it leads to inconsistent results, and that it increases the cost of litigation might have played a behind-the-scenes role in swaying the Florida Supreme Court. Court decisions applying Daubert have been described as “nonuniform, inconsistent, and irreconcilable.”

Constitutional concerns, on the other hand, have not prevented the federal government and the majority of states from adopting the Daubert rule. The Florida Supreme Court made no attempt to address or resolve those concerns, but merely indicated that they were sufficiently grave to warrant its rejection of the Daubert rule “to the extent it is procedural.”

Whether some or all of the Daubert standard is substantive or procedural is a question that will probably need to be resolved in a future case. It is generally recognized, however, that rules governing the admissibility of evidence are procedural since they tell courts how to conduct trials without affecting the substantive rights of litigants. It is therefore likely that the Supreme Court’s decision spells the death of Daubert in Florida, at least for the near future.

A judge

Should Judges Appoint Their Own Expert Witnesses?

The American system of justice is designed to be adversarial. Two sides do battle and a judge or jury decides which side has the better case. To prove their cases, parties often rely on expert witnesses.

The system works reasonably well, but arguments are occasionally made that justice would be better served by relying on “neutral” or “independent” experts who, having been appointed by the judge, would not feel the need to slant testimony in favor of whichever party hired them. Whether that proposal would actually lead to better results is open to question.

Appointed Experts

The Federal Rules of Evidence allow a judge to appoint an expert, with or without the consent of the parties, in both criminal and civil cases. The rule’s explanatory comment states that the rule is meant as a counterweight to the practice of “shopping for experts.”

Of course, the adversarial system anticipates that parties will present evidence that helps them prove or disprove a claim. Finding experts who have something useful to contribute to the jury’s decision should not derogated by the phrase “shopping for experts.”

Judges rarely appoint their own experts because they don’t want to interfere with the fundamental nature of an adversarial system of justice. Judges are understandably reluctant to impose an expert witness on lawyers when the lawyers believe they have chosen experts are better suited to provide expert opinions to the jury.

Judges who have faith in the adversarial system tend to understand that experts frequently disagree, not because they are being paid, but because science is often inexact. Disagreement among experts is nearly inevitable when the subject matter of their testimony is complex, and who is to say that a court-appointed expert is more likely to be correct than one hired by the parties?

A study by the Federal Judicial Center found that federal judges rarely appoint their own expert witnesses. Judges expect the adversarial system to work and they don’t want to influence the outcome of a case by appointing an expert who may benefit one side more than the other. Judges are also concerned about forcing parties to pay for an expert they don’t want or can’t afford.

Complex Issues

Judges may be more inclined to appoint an expert to assist the court when the case will not be resolved by a jury and when issues are complex. In child custody disputes, for example, the court might appoint a psychologist to determine whether one parent would be a better custodian than the other.

Judges who are asked to resolve disputes that involve complex scientific or technical issues might also appoint an expert. Engineering experts are appointed to help courts in cases involving patents and trade secrets, while accounting experts may help judges determine damages in commercial cases. Less often, judges appoint experts in medical malpractice, product liability, and toxic tort cases. Since those cases are usually resolved by juries, however, judges are reluctant to interfere with the trial by insisting on a judicially-appointed expert.

Judge Richard Posner, one of the brightest and most controversial judges on the federal Court of Appeals, has long advocated the appointment of “neutral” experts to educate juries about technological or commercial issues that jurors (and judges) are unlikely to understand. While other commentators — including some experts and judges — have jumped on that bandwagon, the bandwagon is moving slowly and may never reach its intended destination.

Controversial Suggestions

Advocates of court-appointed experts tend to distrust the adversarial system. Sometimes that distrust is rooted in trial outcomes (such as verdicts against big businesses or insurance companies) that are unfavorable to the advocates. Others see those outcomes as proof that the system works just fine.

Distrust of expert testimony has been strongest in cases involving drugs that are alleged to cause health problems and toxic substances that are alleged to harm people who live in a particular area. Businesses and insurance companies, unhappy with the verdicts that juries returned against them, insisted that those allegations were supported by “dubious causation theories,” a concern that gave birth to the Daubert standard. Only experts who have formed opinions using a reliable methodology may testify under Daubert.

Whether judges are capable of evaluating the reliability of a scientific methodology is an open question. Judges are not scientists. As Justice Breyer noted in a concurring opinion, some scientists have suggested that judges should appoint their own experts to help them evaluate the reliability of a party’s retained expert. Yet how is a judge to know that an appointed expert is less biased or more capable than a retained expert?

Perils of Neutrality

When an expert serves the court rather than a party, the expert is said to be neutral. But no expert should be an advocate for anything but the truth. The same is true of judges. If there is a risk that an expert will habitually favor one side in a dispute, that risk may exist whether the expert is retained by a party or judicially appointed. After all, judges are often seen as being “liberal” or “conservative,” and their biases may incline them to appoint experts who share the same biases.

If judges feel the need to appoint experts, they might want to select the experts from a list that has been assembled by the relevant scientific community. That suggestion might overcome the fear that judicial bias would lead to the appointment of a biased expert. But if the group that assembles the list has a bias, a judicially-selected expert may be just as partisan as a retained expert.

When judges do appoint experts, should the jury know that the expert was selected by the court, not the parties? The risk is that juries may place undue reliance on an appointed expert in the belief that “the judge’s expert” must be more reliable than the retained experts. Even if jurors are not told that an expert was court-appointed, the fact that an expert isn’t working for either party is often easy for juries to discern.

Cross-Examining an Appointed Expert

An appointed expert should be subject to cross-examination just like any other expert, but some lawyers fear that a “tough” cross-examination of an appointed expert might incur the wrath of the appointing judge. Fear that upsetting the “judge’s expert” will upset the judge might lead to a timid cross-examination, but the adversarial system requires lawyers to be vigorous as they probe experts to expose the strengths and weaknesses of their opinions.

Since a jury might attach more weight to the opinions of the “court’s expert,” lawyers who cross-examine the expert should look for common ground in the analysis of the appointed expert and that of the party’s retained expert. The best strategy might be to emphasize points of agreement while suggesting that disagreements between the experts are minor. And since expert opinions depend on the facts, the appointed expert might be willing to concede that his or her opinion could change depending on which party’s version of the facts the jury accepts as true.

In the end, skilled advocates in an adversarial system can only do their best to help juries find the truth. Sometimes the system works and sometimes it doesn’t, but it is far from clear that the routine appointment of expert witnesses by courts would improve the accuracy of jury verdicts.


Experts Question Reliability of Forensic Video Evidence

The need for criminal defense attorneys to hire independent expert witnesses has never been more clear, as the reliability of testimony given by expert witnesses who work for the police has increasingly been called into question. Unfortunately, the importance of an independent expert witness to a fair trial isn’t always apparent to defense attorneys or to judges.

Two cases involving robberies of 7-Eleven stores illustrate the importance of retaining a forensic video expert when a criminal accusation is supported by video evidence. In both cases, the defendants were convicted of robbery based on expert testimony that the defendants were the same height as the robber shown on surveillance camera footage. In both cases, independent forensic video experts hired after the defendants were sentenced concluded that the surveillance videos proved the defendants’ innocence.

George Powell III

George Powell III was charged with robbing a 7-Eleven store in Killeen, Texas in 2008. A surveillance video showed a man wearing sunglasses and a baseball cap pointing a gun at the store clerk. The video was broadcast on the news and the police arrested Powell in response to a tip from a television viewer.

At the time of the robbery, the clerk estimated that the robber was 5 feet 6 inches tall. Shown a photo array of faces, she picked Powell’s photograph. She was not aware, however, that Powell is 6 feet 3 inches tall. Other clerks were less confident that Powell was the robber.

It isn’t uncommon for eyewitnesses to be mistaken when they are shown photographs rather than seeing an in-person lineup. The method used to obtain the clerk’s identification of Powell is so unreliable that it was later banned in Texas courts.

To deal with the height discrepancy, the prosecution called Michael Knox as an expert witness. Knox, a retired police officer, testified that he used the science of photogrammetry to determine that the robber in the video was more than 6 feet tall. Knox had no training in photogrammetry and had never before attempted to determine a suspect’s height based on a video image. Powell was nevertheless convicted on the strength of that evidence, coupled with the testimony of a Texas jailhouse informant that was later recanted.

Powell’s family eventually hired two experts who examined the video and determined that the robber was about 5 feet 7 inches tall. The Texas Science Commission then hired Grant Fredericks, who taught video analysis at the FBI National Academy. Fredericks determined that the robber was somewhere between 5 feet 6 inches and 5 feet 9 inches tall. All three expert opinions excluded Powell as a suspect. All three experts agreed that Knox did not follow professional standards in forming his opinion about the robber’s height.

Powell’s defense team has filed a motion challenging the conviction. A district judge will consider the evidence, including the new expert evidence, and make recommendations to the Texas Court of Criminal Appeals as to whether Powell should be granted a new trial.

Michael Hutchinson

A clerk who was robbed at gunpoint at a 7-Eleven in Milpitas, California identified Michael Hutchinson as the robber. The identification was problematic because the robber was wearing a mask. Hutchinson was nevertheless convicted in a 1998 trial.

Hutchinson’s appellate attorney asked the state appellate court to approve funds for a forensic video expert. The attorney told the court that an expert was needed to establish that Hutchinson was not the robber captured on tape by the store’s surveillance camera. Deciding that an expert was unnecessary, the court affirmed Hutchinson’s conviction.

After taking an interest in Hutchinson’s case, the Mercury News hired a forensic video expert to examine the surveillance video. The expert concluded that the robber was much shorter than Hutchinson.

Hutchinson then brought his case before a federal judge. Relying in part on the forensic video expert’s opinion, the judge ruled that Hutchinson’s attorney failed to protect his client’s right to a fair trial. The judge concluded that the attorney should have recognized the need for an expert analysis of the videotape.

The judge’s decision that Hutchinson was entitled to a new trial was affirmed on appeal. The federal appellate court chastised the state courts for failing to fund the hiring of a necessary expert.

Forensic Video Analysis

Forensic video analysis has become increasingly important as more businesses, government buildings, and private homes install video cameras that capture the images of criminal suspects. The April 2016 report by the Texas Forensic Science Commission, prepared in response to Powell’s complaint, recognizes the legitimacy of photogrammetry. At the same time, the fact that different experts arrive at different height estimates when examining the same video “gave the Commission pause and raised concerns as to the state of forensic video analysis.”

The Commission noted that “the subjectivity involved in the different approaches to making a height determination raises questions about inter-analyst reliability within the discipline.” The absence of known error rates, the failure of analysts to standardize an analytical method, and the presence of confirmation bias (where the analyst knows the suspect’s height before undertaking the analysis) all raise questions about whether expert forensic video analysis should be admissible against a defendant in a criminal trial.

Lessons Learned

The cases of Powell and Hutchinson spotlight the importance of independent experts. In both cases, the defense attorney should have retained a forensic video expert to determine whether the robber was the same height as the defendant.

Blindly putting faith in the ability of the prosecution’s expert is a mistake, since experts who work for the police too often see themselves as advocates for the prosecution, not as advocates for the truth. At the very least, a criminal defense attorney who is faced with a prosecution expert in forensic video analysis should read and understand the concerns raised by the Texas Forensic Science Commission.

At the same time, too many judges believe that experts should only testify for the prosecution, not the defense. The Texas court that denied Powell’s request for funding to hire a forensic video expert assumed that an independent expert would add nothing of value to the proof. The court’s conclusion that an independent expert would not have been helpful is belied by recent revelations that forensic video experts employed by police agencies, when left unchallenged by independent experts, contribute to wrongful convictions.

North Carolina

N.C. Supreme Court Adopts Daubert, Excludes Use of Force Expert

Charles McGrady was convicted in North Carolina of murdering his cousin, James Shore Jr. McGrady admitted that he shot Shore but claimed that he acted in self-defense. The trial court denied his request to call a “use of force” expert in his defense.

On appeal, the state’s highest court decided that the federal Daubert standard of expert witness admissibility now applies in North Carolina. Applying that exacting standard, it affirmed the lower court’s exclusion of the expert testimony.

Facts of the Case

McGrady and Shore lived across from each other in a trailer park. They had a long history of combative behavior.

McGrady testified that the night before the shooting, Shore threatened to kill him. The next day, McGrady drove his golf cart to his mailbox. His son, seated next to him, was armed with an assault rifle. McGrady was carrying a 9-millimeter handgun.

As McGrady was driving back to his trailer, he saw Shore shouting and moving toward him. McGrady activated a tape recorder that captured much of the argument between the two men. McGrady accused Shore of threatening to kill him. Shore accused McGrady of shining a spotlight on him the previous night. Another witness testified that it was not a spotlight but the laser sight of an assault rifle that McGrady pointed at his cousin.

The men exchanged a variety of threats. According to McGrady’s son, Shore approached the golf cart and began to shake it. McGrady testified that Shore also threatened them with a knife.

McGrady asked his son to hand him the assault rifle “to defuse the situation,” an act that prompted Shore to reach for the rifle. Whether Shore actually grabbed the rifle was disputed by the witnesses.

McGrady testified that Shore pointed the rifle at his son’s head. McGrady then shot Shore with his handgun. McGrady fired seven shots, four of which struck Shore.

McGrady argued that he acted in self-defense and in defense of his son. To bolster that defense, he wanted to call Dave Cloutier as an expert in “the science of the use of force.” The trial court denied that request and McGrady was convicted of murder.

Admissibility of Expert Testimony in North Carolina

In 2011, the North Carolina General Assembly amended Rule 702(a) of North Carolina’s Rules of Evidence. The version that the legislature adopted tracked the language of the federal rule governing the admissibility of expert testimony. The federal rule is commonly known as the Daubert standard, based on a United States Supreme Court case that defined the trial court’s responsibility in applying the rule.

In 2004, the North Carolina Supreme Court had concluded that “North Carolina is not, nor has it ever been, a Daubert jurisdiction.” The Court was concerned that “the ‘exacting standards of reliability’ demanded by the federal approach” required judges to invade the province of the jury by evaluating “the substantive merits of the scientific or technical theories undergirding an expert’s opinion.”

In McGrady’s appeal, the Court overruled that precedent and held that the “the meaning of North Carolina’s Rule 702(a) now mirrors that of the amended federal rule.” According to the Court, “the General Assembly has made it clear that North Carolina is now a Daubert state.”

The Court concluded that federal precedent construing the Daubert standard should guide North Carolina cases. Of course, as ExpertPages has often noted, federal courts have adopted varying interpretations of the federal rule. Some interpretations are more liberal and others are more restrictive in defining the judge’s role as the “gatekeeper” of expert evidence.

North Carolina had a fairly liberal standard for the admission of expert evidence before the legislature adopted the Daubert standard. The Court concluded that its prior cases will continue to guide judges, but only to the extent that they are not inconsistent with Daubert. For the most part, cases that decided whether expert testimony would be helpful to the jury and whether the expert was qualified to testify will still be good law in North Carolina. The key difference between the old and new standards is that a judge’s assessment of whether expert testimony is reliable will be more rigorous than it was in the past.

McGrady’s Expert

McGrady expected his use of force expert to provide three opinions:

  • the “pre-attack cues” and “use of force variables” present in the interaction between McGrady and Shore made McGrady’s perception of an imminent, deadly assault reasonable and justified the use of deadly force;
  • McGrady’s actions and testimony are consistent with those of someone experiencing the sympathetic nervous system’s “fight or flight” response; and
  • the shots that hit Shore in the back can be explained by reaction times.

The North Carolina Supreme Court concluded that the trial judge did not abuse his discretion in disallowing that testimony. The appellate court agreed that McGrady’s perception of a likely assault was within the jury’s common knowledge and that an explanation of cues (such as threats and the display of a weapon) and variables (such as the age and size of the participants in the dispute) would not add anything to what jurors already understood.

The Court also agreed that Cloutier was not qualified to offer expert testimony about the stress responses of the sympathetic nervous system. Cloutier was not a doctor. He claimed to have “basic knowledge” of brain functioning based on taking college psychology courses, reading articles, and teaching police officers how to deal with stress responses. The Court concluded that while Cloutier “may have been eminently qualified to testify about standard police practices regarding the use of force, he was far less qualified to testify about the sympathetic nervous system.” Whether Cloutier was adequately qualified was a judgment call, and the trial court’s judgment was not so obviously wrong that the court could be said to have abused its discretion.

Finally, the appellate court agreed that Cloutier’s proposed testimony regarding reaction times was unreliable. Cloutier would have testified that a person can turn his body in less time than it takes to perceive a threat and fire a weapon, so Shore might have been facing McGrady when McGrady decided to shoot, but might have turned his back to McGrady before the shots were fired. The trial court thought the proposed testimony was unreliable because Cloutier based his opinion on reaction time studies, but admitted that factors such as clothing, injuries, and initial body position can affect reaction time. Those factors would seem to go to the weight a jury should give to Cloutier’s testimony rather than its reliability. In fact, use of force experts routinely testify about reaction times in cases where the police shoot a suspect in the back. The same standard presumably should apply to civilian defendants, but the Court concluded that the trial court did not abuse its discretion in deciding that Cloutier’s testimony was unreliable.

Implications for Expert Witnesses

In the end, the McGrady case is more important for its definitive ruling that North Carolina now follows the Daubert standard than for its application of that standard to Cloutier’s expert testimony. Other trial judges applying the same standard may have concluded that some parts of Cloutier’s testimony were admissible. In fact, use of force experts are common when police officers are on trial, so the McGrady decision should not be read as prohibiting use of force expert testimony in every case.

Cellphone, signals, wifi

Cellphone Experts Debate Validity of Location Evidence

In criminal cases across the country, FBI agents and local police detectives have testified as expert witnesses concerning the location of a suspect’s cellphone (and presumably the suspect) at the time a crime was committed. Whether law enforcement officers are qualified to give that testimony is a hotly contested question.

The Connecticut Supreme Court is the latest jurisdiction to consider whether cellphone location evidence is sufficiently reliable to be admitted at a criminal trial. The court’s decision will contribute to a continuing debate about the validity of the expert evidence, particularly when the expert witnesses are police officers with no background in engineering or telecommunications.

Eugene Edwards’ Appeal

Eugene Edwards Jr. was convicted of robbing Lieslotte Worysz, age 83, in Wethersfield, Connecticut. The prosecution argued that Edwards followed the woman home from the grocery store, entered her garage as she exited from her car, put his hand on her car door while brandishing a gun, stole her money and jewelry, and fled. The jury found Edwards guilty.

Edwards was also charged with committing a similar robbery of an elderly woman in Berlin, Connecticut three weeks earlier. The jury found Edwards not guilty of that crime.

Worysz described the robber as a black man between the ages of 35 and 40. She testified that the robber was holding a black gun. When the police showed her pictures of potential suspects, she said they all looked alike to her.

Worysz noticed a car behind her as she drove home. A surveillance video at the grocery store captured the car that Worysz described. Edwards was one of three people who, according to records of people with prior police contacts, owned a similar car. The police did not inspect the other cars. The car on the video had a broken brake light, but the brake lights on Edwards’ car were working.

Worysz said that the robber held her wallet and a garage door opener. A DNA analysis eliminated Edwards as a possible source of DNA found on the wallet and opener.

A fingerprint analyst could not match a partial print that was taken from Worysz’ car to Edwards, although a different analyst testified that the partial print came from Edwards’ left hand. Worysz testified that Edwards was holding the gun in his left hand. The defense argued that Edwards could not have opened the car door using a hand that was holding a gun. In any event, Connecticut law does not permit a conviction to be based on fingerprint evidence alone when the print was taken from a car that has been parked in a public place.

The police searched Edwards’ home and found a black BB gun with an orange tip. Worysz did not describe the gun she saw as having an orange tip. No jewelry or other crime proceeds were found in a search of Edwards’ car and residence about a week after the robbery.

Expert Testimony

Detective Christopher Morris testified as a cellphone expert based on his attendance at a three-day police training session in cellphone investigations. He opined that Edwards’ cellphone connected to towers near Worysz’ home and near the store where Worysz was shopping on the day of the robbery. He also testified that cellphones connect to the nearest tower, although he acknowledged that facts such as weather, network congestion, network maintenance, topology and foliage can all affect the cellphone’s connection to a particular tower.

The prosecution called a Verizon employee to authenticate the records upon which Morris relied, but the trial court ruled that the employee was not an engineer and was not qualified to offer any opinion as to whether Edwards’ phone would have connected to the nearest tower. However, the court held that Morris was qualified as a “police expert” to testify about cellphone locations based on his training and experience.

Morris gave no testimony about peer-reviewed studies that validated his methodology. He gave no testimony about error rates that occur when his methodology is used to determine cellphone locations. The prosecution offered no evidence that Morris was trained by scientists or engineers or that his training was based on accepted scientific principles. The Connecticut Supreme Court agreed to decide whether a police witness who is not an engineer and has no scientific training other than “police training” is qualified to give reliable testimony about cellphone locations.

Controversial Evidence

Connecticut joins a growing number of jurisdictions that are tackling the use of law enforcement officers to testify as expert witnesses regarding cellphone tracking. Some independent experts, like Michael Cherry, say that their testimony is based on “junk science.”

Cherry notes that police officers “tend to confuse the location of the cellphone with the location of the cell tower.” According to Cherry:

People like to say that the phone goes to the nearest tower. It goes to the clearest tower within range, not always the closest tower. You could be sitting on your living room couch and you could make four phone calls and each call would use a different tower.

Getting that point across to jurors may require defense attorneys to retain the services of independent experts. The initial question confronting courts, however, is whether police officers who have no background in science are able to give reliable testimony about cellphone locations based on brief training sessions that are taught by other police officers who have no background in science.

Judicial Decisions

As ExpertPages has noted in the past, different trial courts have reached different conclusions about the admissibility of expert testimony concerning cellphone locations. In Maryland, Adnan Syed was recently granted a new trial because his lawyer failed to cross-examine a state’s expert witness about the reliability of cell tower data that allegedly placed him near the site of the victim’s burial.

Lisa Marie Roberts, convicted of murder in Oregon, was also granted a new trial based on her attorney’s failure to challenge questionable expert cellphone location evidence. A judge in that case ruled that there were serious doubts about Roberts’ guilt.

A federal judge in Chicago refused to allow an FBI agent to testify about a cellphone location in a kidnapping case. The court concluded that the agent’s “chosen methodology has received no scrutiny outside the law enforcement community” and that the reliability of that methodology had therefore not been established.

Other courts have routinely admitted cellphone tracking evidence, perhaps because defense lawyers do not realize that they have grounds for challenging its admissibility. Evidence professor Edward J. Imwinkelried encourages lawyers to use their own experts to challenge law enforcement agents who claim that they can determine the location of a cellphone using cellphone tower records.


Can a Computer Program Be an Expert Witness?

When DNA testing is too complex for police crime labs, the labs sometimes outsource their testing to a company like Cybergenetics. Most crime labs can handle DNA testing when the DNA to be analyzed comes from one person, but the process is much more complex when DNA from multiple sources has been mixed together.

Cybergenetics has developed a “probabilistic genotyping” software program called TrueAllele. The software uses algorithms that make judgments about how to separate DNA samples in order to create an individual DNA profile for each contributing source.

Computer Programs as Expert Witnesses

According to Cybergenetics, the TrueAllele program is superior to human analysts. Human experts, however, have the capacity to admit that they might be mistaken, particularly when an apparent flaw in their judgment is pointed out in court. The inability to convince a program that it reached an incorrect result is one reason why human experts might be preferable to computer software.

The use of a computer program to provide an expert opinion has sparked a controversy in the criminal justice system. While lab analysts can be cross-examined, it isn’t possible to cross-examine a computer program. In lieu of cross-examining TrueAllele, defense attorneys would like to have their own experts examine the program’s source code to determine whether the program might be flawed. Asserting that the source code is proprietary information, Cybergenetics refuses to release it, making it impossible to determine whether the program actually functions as intended.

The developers of TrueAllele claim that the program removes human bias from the testing process. But perhaps that claim reflects the bias of Cybergenetics, which makes money when outside agencies rely upon the program. Is TrueAllele really more accurate than human experts or is that a marketing claim?

Software Marketing

Cybergenetics offers to conduct a free preliminary analysis for police agencies. If the results show a probable DNA match, the agency can then decide to pay for a full analysis, complete with a report that can be offered as evidence at trial. That model provides an incentive to report a match — without one, Cybergenetics doesn’t get paid.

Cybergenetics’ primary competitor is STRmix, a program developed by a New Zealand-Australia collaboration and marketed by Nichevision in the United States. The FBI uses STRmix. David Balding, a professor of statistical genetics at the University of Melbourne, cites a study in which TrueAllele and STRmix were both used to examine a lab-created sample and returned “significantly different results.” That study suggests that one or both of the programs might be seriously flawed, but which one?

While both Cybergenetics and Nichevision claim that their programs are reliable, the studies that purport to demonstrate their reliability were conducted by the programmers, not by independent testing authorities. The recent White House PCAST report assessing the reliability of expert evidence noted that independent research is needed to verify those claims.

Cybergenetics argues that its internal test results should be sufficient, but Cybergenetics has an economic incentive to produce validation results that will help it sell its services. In the absence of independent testing, why should a court assume that probabilistic genotyping software is reliable?

Admissibility in Court

Courts that have considered whether to admit DNA testing results generated by computer programs have arrived at mixed results. A New York judge disallowed STRmix results in a high-profile case involving the strangulation death of 12-year-old Garrett J. Phillips. An earlier TrueAllele test in that case returned an inconclusive result. The judge decided that the prosecution failed to demonstrate the reliability of the STRmix program.

Other courts have decided to admit the evidence. For example, police officers in Onondaga County, New York stopped a car that was being operated without headlights. The car’s occupants fled into a park and shots were fired. Officers found a gun in the park, but they did not apprehend, and could not identify, any of the car’s occupants.

Police investigators determined that Frank Thomas owned the car. They had no other evidence that tied him to the gun. The local crime lab found the DNA of four to six people on the gun. Because the DNA was mixed, separating it and matching it to a particular suspect was beyond the crime lab’s ability.

The lab sent the samples to Cybergenetics. An analysis by the TrueAllele program computed a very high probability that DNA on the gun matched that of Thomas (or someone related to him). Believing he should not be required to take Cybergenetics’ word for the reliability of its program, Thomas’ lawyer asked for the program’s source code so that an expert could determine whether the program actually works. Cybergenetics refused to provide it and Thomas was convicted of reckless endangerment for firing the handgun. His case is on appeal.

Challenging Computer Software as an Expert Witness

A coding error in the STRmix program affected test results in at least 60 criminal prosecutions in Australia. Whether other errors exist in the source code can’t be determined without analyzing it, but the companies that developed TrueAllele and STRmix refuse to provide their source codes to defense attorneys.

Defense attorneys maintain that convicting defendants on the basis of “secret evidence” is inconsistent with constitutional values that emphasize the importance of cross-examination and disclosure of the basis for expert opinions. Both are fundamental to a fair trial, but it isn’t possible to cross-examine a computer program, and exposing flaws in the program isn’t possible without access to the source code.

Defense attorneys faced with DNA evidence that was produced by software rather than human experts can use their own expert witnesses to point out the inherent uncertainty of test results that cannot be validated by independent, unbiased scientists. Defense attorneys can also challenge the admissibility of evidence that depends upon an unproven methodology and that frustrates the constitutional right to confront a witness. Finally, defense attorneys can continue to demand to have the program’s source code analyzed by their own forensic computer experts.

Until appellate courts begin to recognize and address the problems caused by using software as an expert witness, the admission of probabilistic genotyping test results in a criminal trial will continue to raise serious concerns. As the Electronic Privacy Information Center contends, “Secrecy of the algorithms used to determine guilt or innocence undermines faith in the criminal justice system.”

Gavel and Stethoscope on Reflective Table

Ethical Challenges for Medical Expert Witnesses

An article entitled Ethical Challenges for the Medical Expert Witness in a recent issue of the AMA Journal of Ethics poses a hypothetical problem and asks expert medical witnesses to consider their ethical duties if they find themselves in a comparable situation.


The article poses the following hypothetical problem. A behavioral neurologist who occasionally testifies as an expert witness is asked to review the records pertaining to a personal injury victim who sustained a head injury. The victim was exiting from a parking lot when a truck collided with her vehicle. The victim’s attorney wants the neurologist to determine whether the collision was the most likely cause of the victim’s chronic headaches and cognitive dysfunction.

The medical records are ambiguous. Neither the police report nor the reports of the paramedics who arrived at the scene suggest that the victim was confused or disoriented. The records do not clearly state that the victim lost consciousness. A loss of consciousness and a period of confusion or disorientation are typical symptoms of a mild traumatic brain injury. The expert worries that if she testifies, she will need to reveal her concern that the documents do not clearly establish a loss of consciousness or confusion, facts that might undermine the belief that the victim suffered from a traumatic brain injury. She wonders if she should reveal her concerns to the attorney who hired her, or if she should simply decline further participation in the case.

Consequence of Providing an Expert Opinion

The authors of the article suggest several considerations that should guide a physician’s ethical judgment about acting as an expert witness. The first requires the physician to consider the consequences to the parties. Testifying that the victim suffered from a mild traumatic brain injury, when the expert doubts that the facts establish such an injury, would undermine the victim’s case, might prolong the litigation, and could cause the victim to suffer further stress as she pins her hopes on unachievable goals.

The expert could also experience professional consequences from giving less than honest testimony, including sanctions imposed by a state licensing board. She might also be sued by the trucking company if she provides false testimony that causes a judgment to be entered against it.

Of course, all of those concerns could be alleviated if the expert testifies truthfully. It seems self-evident that the expert should share her concerns with the attorney who hired her. If the attorney still wants her to testify, she should make clear that she does not know whether the victim did or did not lose consciousness or whether she appeared to be disoriented. She was not present at the accident scene and only the eyewitnesses who were present would have that knowledge.

It is up to the jury, not the expert, to decide the facts of the case. The expert is free to give conditional testimony if she chooses. In other words, the expert can make clear that her opinion is conditioned on certain facts being true, and that she cannot be certain whether the evidence will prove those facts.

Daubert Analysis

The authors suggest that the expert’s opinion would not satisfy the Daubert standard for the admissibility of expert witness testimony. They suggest that:

  • The testimony is not based on sufficient facts.
  • The testimony would not be based on reliable principles and methods.
  • The expert cannot reliably apply scientific principles to the facts of the case.

Whether the authors’ Daubert analysis is correct depends upon the testimony that the expert would give. Whether expert testimony is admissible under Daubert is for the court to decide, not the expert. Whether the attorney will want the expert to testify, after being advised about the expert’s honest opinion, is a question for the attorney to answer, not the expert.

Experts in most states are entitled to answer hypothetical questions. The expert might be asked a question along these lines: “Assuming the victim lost consciousness and experienced disorientation after the accident, do you have an opinion whether the victim’s current headaches and cognitive dysfunction were caused by the accident?” It would then be the attorney’s responsibility to introduce evidence to support those assumptions, which might come from the victim herself.

It is not unethical to give an honest answer to a hypothetical question. An expert neurologist is not a detective. Police reports are not always accurate and conflicting recollections are not uncommon. The expert should disclose her reservations to the attorney who hires her, and if the attorney points to facts suggesting that the victim suffered disorientation and a loss of consciousness shortly after the accident, the expert should feel free to render an opinion based on those facts, while acknowledging in her testimony that whether those facts are true is for the jury to decide.

Professional Guidance

The best advice in the journal article comes from the American Medical Association:

The AMA Code of Medical Ethics Opinion 9.07 expressly states that physicians who serve as expert witnesses must deliver honest testimony grounded in “recent and substantive experience or knowledge in the area in which they testify, and be committed to evaluating cases objectively and to providing an independent opinion.” … The opinion also states that physicians cannot let financial concerns drive the nature of testimony, and it calls on medical professional societies and state licensing board to sanction those who give false or misleading testimony.

In other words, an expert should be competent to render an opinion and should do so honestly. As long as an expert witness follows those simple rules, the expert should have no difficulty meeting ethical standards.