Experts Question Reliability of Forensic Video Evidence

Written on Wednesday, February 8th, 2017 by T.C. Kelly
Filed under: Research & Trends

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.

About T.C. Kelly

Prior to his retirement, T.C. Kelly handled litigation and appeals in state and federal courts across the Midwest. He focused his practice on criminal defense, personal injury, and employment law. He now writes about legal issues for a variety of publications.

About T.C. Kelly

Prior to his retirement, T.C. Kelly handled litigation and appeals in state and federal courts across the Midwest. He focused his practice on criminal defense, personal injury, and employment law. He now writes about legal issues for a variety of publications.