Another day, another wet blanket thrown over eyewitness reports in the Washington-area sniper investigation.
Police said Thursday that one witness's vehicle and weapon descriptions at the latest killing scene were bogus and reports of a foreign-looking or Hispanic shooter also were apparently off base. The backtrackinionally misled the public in stating that the shooter drove a cream-colored van and used an AK-74 assault gun. Beyond that, bystanders have offered a variety of descriptions that police have declined to endorse.
The suddenness of the sniper attacks terrorizing suburban Washington and the shock of seeing people killed help explain why witnesses have been unable to provide a solid description of the attacker, experts say.
Witness accounts are distorted by fear and the tendency of bystanders to focus immediately on the victim, giving the shooter crucial seconds to disappear.
"The normal reaction to fear is not one of becoming a really good, attentive eyewitness," said Gary Wells, an Iowa State university psychologist who has studied witness testimony for 25 years. "The normal reaction is to flee, to help the victim, to protect yourself."
The ninth killing, of Linda Franklin outside a Home Depot store in Falls Church, Va., on Monday night, was the first witnessed by a number of bystanders. Authorities at first believed important new clues were finally at hand.
"I am confident that that information is going to lead us to an arrest in the case," Police Chief Tom Manger of Fairfax County, Va., said Tuesday.
But that confidence soon began to unravel. And on Thursday, police appealed to the public not to give credence to reports that the shooter drove a cream-colored van, shot with an AK-74 and had dark or olive skin.
People looking only for those characteristics may well miss the real killer, authorities said. Officials continued to display composite drawings of vehicles that might be the killer's -- a white box truck and a white or very light Chevrolet Astro van or Ford Econoline van.
"We get this noise, this confusion out there that gives people tunnel vision and makes them focus in on things that are not appropriate," said Montgomery County Police Chief Charles Moose, who is leading the investigation.
Police have also given tips on how to be an effective eyewitness. Among them: Stare in the direction of the bullet noise, carry a pen to take notes; if necessary, write down details on your hand.
In addition, witnesses should not "contaminate" their memories by comparing notes with other people or the media, police said.
Mistaken eyewitness reports are the leading cause of putting the wrong people behind bars, said Nina Morrison, an attorney with Yeshiva University's Innocence Project that documents wrongful or questionable convictions.
Morrison endorsed the police tip to write down details immediately and said witnesses often -- and understandably -- focus on the weapon rather than the person holding it.
"Many of the factors that contribute to mistaken identity are not within the witness's control," she said Thursday, "but what we have seen is that the initial description is far more accurate than one that has been given over time."
Uncertainties over witness accounts have increased pressure for a moratorium on the death penalty. A recent Associated Press review of 110 convictions overturned because of DNA evidence found that nearly two-thirds were based on erroneous eyewitness testimony.
Wells of Iowa State said the sniper case is especially hard for witnesses because of the suddenness of the attacks.
With the sniper, "There's street noise, the attention is directed to the effect of the gun. By the time they realize this person's been shot, they look around and it's too late," said Wells.
Ira Robbins, an American University criminal justice professor, agreed that chaos confuses.
"Everybody was running for cover, and witnesses who reportedly saw the shooter get back into a car -- what if that was someone else fleeing for safety?" he asked. "There are too many other things going on, it ties in with distraction." The poor lighting in the parking lot would also have confused witnesses, he said.
The American Bar Association has warned that eyewitness reports can be thrown off by race, stress, lighting, a focus on weapons or other features instead of faces, the length of time a witness sees a suspect, and the time between the crime and the identification.