Most state and local crime lab employees are honest and hard-working, but as federal appellate Judge Alex Kozinski recently noted, some see their job as helping prosecutors obtain convictions, not as finding the truth based on an objective analysis of evidence. Whether from laziness, poor training, misguided loyalty, or pressure applied by law enforcement agencies, government crime lab employees too often produce inaccurate results, and sometimes falsify evidence.

A new investigation suggests that prosecutors have been slow to correct those problems. Until crime labs are able to assure that forensic test results used as criminal evidence are accurate, it will continue to be vital for criminal defense attorneys to retain their own forensic experts to review crime lab results.

Problematic Crime Lab Results

Last year, the Washington Post reported that “nearly every examiner in an elite FBI forensic unit gave flawed testimony in almost all trials in which they offered evidence against criminal defendants over more than a two-decade period before 2000.” The examiners overstated forensic matches of hair comparisons “in ways that favored prosecutors.”

Perhaps the FBI lab employees relied on flawed science, although they should have known that they were basing their conclusions on “incomplete or misleading statistics.” According to the Post, the experts testified as they did because they were trained to give testimony that favored prosecutors.

An article in The Atlantic (“CSI Is a Lie”) reports that many state and local crime lab employees have testified about incorrect or unreliable lab results, usually because of poor training or sloppy work. Cited examples include:

• In St. Paul, “faulty techniques and ignorance of basic scientific procedures” contributed to “major errors.”
• In Colorado, inadequate training contributed to errors in the measurement of alcohol in blood samples.
• An audit in Detroit “uncovered serious errors in numerous cases” due to “sloppy work” that “probably resulted in wrongful convictions.” The police crime lab was shut down as a result of the audit.
• Three trace-evidence technicians in Philadelphia, charged with examining evidence for traces of blood and semen, flunked their accreditation exams after working for a year, casting doubt on the accuracy of their test results.

Last year, crime lab technicians were found to be tampering with evidence in Oregon and Delaware. A complete list of reported crime lab scandals establishes that the problem has a nationwide scope.

Deliberately False Crime Lab Results

Even more serious are the cases in which crime lab analysts were pressured to lie or to withhold test results that did not support the prosecution’s theory of guilt. The Houston Crime Lab stands as the most notorious example of crime lab analysts who deliberately slanted or fabricated testimony to favor the prosecution. That scandal spurred reform, although the reform efforts did not prevent a toxicologist who testifies for the prosecution in Houston DWI trials from giving false testimony about her credentials.

A more recent example comes from North Carolina, where an independent investigation determined that North Carolina’s State Bureau of Investigation “withheld exculpatory evidence or distorted evidence in more than 230 cases over a 16-year period.”

Three of those cases resulted in executions. There was widespread lying , corruption, and pressure from prosecutors and other law enforcement officials on crime lab analysts to produce results that would help secure convictions. And the pressure worked.

The state’s training manual made clear that the job of North Carolina’s forensic experts was to help secure convictions, not to present objective evidence so that a jury could find the truth.

Prosecutors Resist Remedies

Perhaps the most shocking example of dishonesty occurred in Massachusetts, where drug lab analyst Annie Dookhan made it her mission to get drug users “off the streets.” The easiest way to accomplish that mission was to falsify “tens of thousands of reports, often marking results as ‘positive’ without testing a substance.” Dookhan served a short prison sentence for committing perjury, but tens of thousands of defendants who were convicted and sentenced on the basis of falsified lab test results have never received a remedy.

The ACLU and other organizations have asked the court system to vacate 24,000 Massachusetts convictions that were tainted by Dookhan’s fraudulent reports. Prosecutors, however, have resisted that request, arguing that each defendant should file his or her own motion to challenge the conviction, a process that would take years while overwhelming the state’s public defender system.

An investigation by ProPublico found that prosecutors initially denied that they had any obligation to inform potentially innocent defendants that fraudulent evidence may have contributed to their convictions. After resisting that obligation for four years, prosecutors finally mailed a notice that failed to identify the sender and lacked essential information. Thousands of those notices were returned as undeliverable.

ProPublica notes that the reluctance of prosecutors to disturb convictions based on tainted evidence is not limited to Massachusetts. For example, many convictions have been based on unreliable field tests for drugs that are never confirmed by crime lab testing, but prosecutors in Las Vegas and Houston have been slow to track down individuals who were wrongly convicted.

It is understandable that prosecutors want convictions of guilty defendants to stand, but those convictions should not be based on unreliable or fraudulent forensic evidence. As Matthew Segal, the legal director of the ACLU of Massachusetts, said: “If you think that the person is guilty, then your obligation is to go out and get a clean conviction, not to protect the dirty conviction, the tainted conviction.”

Solving the Problem

When crime labs are dedicated to serving the police, and particularly when they are part of a police agency, experts are more likely to see themselves as advocates for the police rather than advocates for the truth. That problem prompted the National Academy of Sciences to recommend making the government’s forensic experts administratively or financially independent of law enforcement agencies.

Until that happens, the important role played by private forensic experts in a criminal case cannot be overstated. Defense attorneys can no longer assume that a report prepared by a crime lab analyst is accurate or unassailable. Retaining a private expert to conduct an independent analysis of forensic evidence is often a critical means of fulfilling a defense attorney’s duty to provide effective representation to the accused.