Three people, including the teacher raped in her Towson apartment, picked Bernard Webster from a police lineup in 1982, essentially ensuring the Baltimore man's conviction.
Two years later, two boys from Rosedale said they recognized Kirk Bloodsworth as the man who walked away from Becky's Pond with 9-year-old Dawn Hamilton, who was later found raped and murdered.
This fall, Montgomery County police received tips about a white truck or van speeding from the sniper shootings and searched scores of matching vehicles. The suspects charged in the killings were driving a blue Chevrolet sedan.
For decades, witness identification has played a key role in criminal investigations, directing police to suspects and swaying juries. But a wave of DNA-based exonerations, including those of Bloodsworth in 1993 and of Webster this month, have many questioning this once-basic piece of evidence.
Some attorneys, academics and even the Justice Department have recommended basic changes to the way officers collect witness information. Others have encouraged court systems to address the growing body of research showing that witnesses, despite best intentions, are often wrong.
"When people witness a crime, whether they're the victim or a bystander, they're taking in a lot less information, and a lot less detailed information, than they may think," said Gary L. Wells, a professor of psychology at Iowa State University who has conducted research on this topic since the early 1980s.
But change has come slowly. While some districts -- most notably the state of New Jersey -- have adopted these recommendations, most have not.
In Maryland, few if any police departments have changed the way they conduct live lineups and photo arrays to correspond to a policy backed by the Justice Department. The departments say they already take precautions to ensure witness credibility.
In addition, Maryland judges are not required to let experts talk to jurors about the fallibility of witness testimony. And the state's stock jury instructions about such testimony are outdated and actually contradict current science, defense attorneys say.
'God knows how many'
"You know, it's really scary," said defense attorney Carroll McCabe. "We see all the people now who have been proven innocent through DNA. God knows how many people have been falsely convicted of armed robbery who will spend many years in jail because there's no DNA to exonerate them."
The Innocence Project, a New York-based group that works to identify and free those wrongly convicted, estimates that incorrect eyewitness testimony helped convict 70 percent of the people subsequently exonerated by DNA evidence.
Extensive research has been conducted on why people so often misidentify suspects.
"People are very suggestible," said Yale Law School Professor Steven Duke. "We just don't remember what we see."
A classic law school exercise proves the point. After a staged surprise attack, students are told to write descriptions of the "suspect" they just saw.
"You get an incredible range, from age, height, weight to race," said University of Maryland Law School Professor Douglas L. Colbert. "I remember that there was a disproportionate number of witnesses who identified the perpetrator as a person of color."
Stress, psychologists say, makes memory worse. The idea that a victim will never forget the face of an attacker is simply a myth, they say.
"Jurors believe eyewitness accuracy is tied strongly to confidence," said Amy L. Bradfield, an assistant professor of psychology at Bates College in Maine who has written extensively on misidentification. "It turns out there is a small relationship between confidence and accuracy. You can have this really confident, compelling witness who can also be wrong."
The teacher who identified Webster as her rapist remains convinced he is guilty, prosecutors say, even after DNA tests exonerated him.
Small changes in policy
Researchers say police can limit misidentifications with small changes in policy. Witnesses should look at possible suspects or their pictures one at a time, the researchers say, rather than in a group. That way, witnesses are comparing images to their own memory, not picking the person who looks most like the attacker compared with other photographs or people.
Researchers also say that someone unfamiliar with the suspect should run the lineups rather than a detective working on the case. There are too many ways for an officer involved in a case to unconsciously push a witness to one choice or another, according to Wells and other psychologists.
The Justice Department supported this research in its 1999 "Eyewitness Evidence" guide.
"Scientific research indicates that identification procedures such as lineups and photo arrays produce more reliable evidence when the individual lineup members or photographs are show to the witnesses sequentially -- one at a time -- rather than simultaneously," the guide states. "Similarly, investigators' unintentional cues (e.g. body language, tone of voice) may negatively impact the reliability of eyewitness evidence."
In Illinois, where Gov. George Ryan declared a moratorium on executions in 2000, the Governor's Commission on Capital Punishment has recommended all law enforcement agencies follow those guidelines.
In New Jersey, police departments changed their policies more than a year ago in a move prompted by the judiciary, said state Deputy Attorney General Lori Linskey.
State judges, she said, "were really concerned about all these exonerations taking place across the country. They had let it be known that unless we took steps to make the system better, they would take steps to limit the use of eyewitness testimony in trial."
In New Jersey, the state attorney general has authority over all county prosecutors and police departments. But in other states, including Maryland, it is more difficult to prompt broad-based change.
The Maryland attorney general's office deferred to police when asked about lineups and photo arrays. Patrick L. Bradley, deputy director of the Maryland Police and Correctional Training Commissions, said the agency teaches basics on lineups but leaves the details to local departments.
In Baltimore County, a detective involved in a case shows witnesses the photos simultaneously, spokesman Bill Toohey said.
Toohey said it was unclear how showing pictures one by one would diminish unintentional bias. He also said the department would not want an uninvolved officer to run the lineups because that officer would then have to spend time in court on the case, he said.
"That would slow down the process in many ways," he said.
Baltimore City police have a similar policy, said Col. Robert Stanton, chief of detectives.
Stanton said he had not heard of the studies showing the benefits of sequential photo arrays and lineups.
He said city police take steps, such as changing the order of a lineup, to ensure witness credibility. "The detectives want a correct ID as much as the victim does," Stanton said.
Maryland's judiciary has not recently discussed the issue, said Jeff Welsh, spokesman for the Court Information Office.
That frustrates some defense attorneys, who are critical of the state's standard jury instructions in which jurors are told to consider the certainty and confidence of witnesses -- characteristics that do not indicate accuracy, research shows. Some defense attorneys also say it should be easier to introduce experts on witness testimony.
But mainly, defense attorneys and other legal experts say they are worried that innocent people are going to prison.
"I receive letters almost weekly from people who ask for someone to look into their cases," said Colbert, the Maryland law professor.
"I don't know what to do with those letters most of the time. There are very few people who will take on these cases on a pro bono basis," he said. "It takes an enormous effort to investigate a wrongful conviction based on misidentification.
"Yet I am convinced there are many people who continue to be wrongfully convicted on the basis of eyewitness identification."