Six-pack photo lineups -- perhaps the single largest cause of wrongful convictions.
Frustrated with a string of wrongful convictions, the Dallas police department is now the nation's largest force to use sequential blind photo lineups -- a widely praised technique designed to reduce mistakes made by witnesses trying to identify suspects.Here is the complete AP story: Dallas police pioneering new photo lineup approach.
Dallas is not the first department to use the pioneering method. But experts hope that by using it in the county that leads the nation in exonerating wrongly convicted inmates, Dallas will inspire other departments to follow suit.
"If Dallas can do it ... then others are going to rise to the occasion," said Iowa State psychology professor Gary Wells, a national expert on police lineups.
The department switched to sequential blind lineups in April. Before that, Dallas police administered most lineups using the traditional six-pack -- law-enforcement lingo for mounting six photos onto a folder and showing them to a witness or victim at the same time. In sequential blind lineups, mug shots are shown one at a time. Detectives displaying the photos also don't know who the suspect is, which means they can't purposely or accidentally tip off witnesses.
Showing possible suspects all at once tends to make a witness compare the mug shots to one another, Wells said. But if they are shown sequentially, "witnesses have to dig deeper, compare each person to their memory and make more of an absolute decision."
An analysis of 26 recent studies shows that presenting mug shots sequentially instead of simultaneously produces fewer identifications but more accurate ones, Wells said.
Nationally, more than 75 percent of DNA exonerees who have been released since 1989 were sent to prison based on witness misidentification, according to The Innocence Project.