The Associated Press
DALLAS — Police in Dallas, where numerous convictions based on eyewitness testimony have been overturned, are taking part in a study to determine the best way to prevent witnesses from picking the wrong suspects in photo lineups.
Typically a detective shows a witness at least six pictures of possible suspects at the same time, but critics say the detective's body language and verbal cues can unintentionally taint results. As part of the study, Dallas police will use "sequential blind lineups" in which someone who doesn't know who the suspect is shows the photos one at a time.
Experts say the wrong person is less likely to be chosen if photos are viewed sequentially. It also keeps a witness from comparing one person to another and picking someone who closely resembles the criminal.
Misidentifications are a key factor in an estimated 75 percent of the 220 wrongful convictions exposed by DNA testing nationwide since 1989. Dallas County has had more DNA-based exonerations than any other place in the nation since 2001, when state law began allowing post-DNA testing.
All but one of the 19 DNA-based exonerations in Dallas County were due to faulty eyewitness testimony, according to a Dallas Morning News investigation published last fall. Dallas police were the arresting agency in 13 of those cases.
As part of the study, which must include at least 800 lineups, only detectives in assaults and robberies will use the study's methods.
Detectives will load six photos into laptops. One picture will be that of the suspect; the other five will be "filler" pictures of people with similar features.
A computer program will randomly determine whether witnesses should view the lineup simultaneously or sequentially. The computer will then decide whether the computer or a detective will conduct the lineup.
The Washington, D.C. -based Urban Institute, a nonpartisan economic and social policy research group, is in charge of the Dallas study. Research is scheduled to begin early this year, an official said.
"We hope to determine what is the best practice and implement policies accordingly," Dallas police Assistant Chief Ron Waldrop told The Dallas Morning News in Thursday's edition.
Copyright 2013 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
Seven other police departments in Texas use sequential blind lineup methods, including the Dallas suburbs of Richardson and Lewisville.