Forensic science not much science, study says

Experts disagreeing over same evidence reflects dilemma

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According to a congressionally mandated report released last week, the term "forensic science" is a misnomer because many of the disciplines don't deserve to be called science at all.

In what former Allegheny County coroner Dr. Cyril H. Wecht called "a revolutionary event in the field of forensic science," the National Academy of Sciences announced the results of a long-awaited study of forensic crime-solving techniques -- and it wasn't kind.

The report called for a federal overseer to set standards for crime labs and called into question the use of many common practices.

"With the exception of nuclear DNA analysis, however, no forensic method has been rigorously shown to have the capacity to consistently, and with a high degree of certainty, demonstrate a connection between evidence and a specific individual or source," the report states, later questioning, "whether -- and to what extent -- there is science in any given forensic science discipline."

The report's authors take care not to question cases currently in the system or past convictions. Although DNA evidence -- which the report praises as incredibly precise -- is frequently used to prove wrongful convictions, its forensic cousins like fingerprints, footprints, bite marks and tool marks can help convict the innocent.

That was the case when Drew Whitley was convicted of a murder at the McDonald's near Kennywood Park, based partly on evidence that strands of hair found in the killer's mask were similar to his. After he served nearly 18 years in prison, Mr. Whitley was exonerated in 2006 when DNA tests showed definitively that those hairs weren't his.

Allegheny County District Attorney Stephen A. Zappala Jr. said his office acts quickly to drop charges when clear evidence of a false conviction arises -- as it did for Mr. Whitley and Thomas Doswell, who was exonerated of rape charges in 2005.

Mr. Zappala called the county's crime lab personnel the best in the country and said the methods and science they employ are sound.

"The idea is not to railroad somebody," Mr. Zappala said. "The idea is to get really strong objective evidence that we can use."

That objective evidence, Mr. Zappala said, often can be analyzed by a jury just as well as any expert. Prosecutors now can show jurors side-by-side or overlapping comparisons of fingerprints and bullets on video screens, and let the jurors determine if they match up.

In Allegheny County, that evidence is put together by the crime lab, which is considered to be among the best in the country. It is scheduled to move into a new $22 million medical examiner's facility in the Strip District this year.

Dr. Wecht, a nationally renowned forensic pathologist, had a hand in building that reputation, but he said he fears that the lab might be drifting away from something the National Academy of Sciences report calls vital -- independence.

Dr. Wecht, who has feuded publicly with Mr. Zappala in the past, accused the district attorney of "unbridled attempts to take over" the crime lab.

The lab is separate from the district attorney's office, and it reports to the county executive. Mr. Zappala is in the midst of restructuring the system somewhat, but his spokesman, Mike Manko, said it is merely an attempt to streamline communication between prosecutors and the crime lab.

"The district attorney already has taken a position that cases were coming out of the crime lab too slowly," Mr. Manko said. "That is why he wanted to see significant changes."

But a more subtle problem is for investigators to be biased toward law enforcement officials who are trying to confirm the identity of a suspect they've targeted.

Occasionally, "forensic scientists think of themselves as part of a law enforcement team -- and that's not good," said Jim Fisher, former FBI agent, retired criminalistics professor at Edinboro University and author of "Forensics Under Fire: Are Bad Science and Dueling Experts Corrupting Criminal Justice?"

Mr. Fisher, of New Wilmington, Lawrence County, said when prosecutors and lab technicians work too closely, the scientists can be "under pressure to oversell evidence."

Veteran Allegheny County defense attorney James Wymard said evidence presented by experts takes on an air of certainty that makes them difficult to cross-examine.

"You're talking to a scientist, to begin with, who's a professional and has been trained," Mr. Wymard said. "Jurors are going to be impressed by that."

But Mr. Wymard and other defense attorneys frequently provide their own experts to rebut prosecution testimony. This can result in two scientists having different opinions on the same evidence -- which Mr. Fisher said isn't consistent with "science" at all.

Dr. Wecht, who has testified as an expert witness in countless cases, often countering another expert, said that's because forensic science is inexact by nature.

"Absolute sciences are math, chemistry and physics," Dr. Wecht said. "Medicine, including pathology, is not an exact science. ... You have to be careful. You have to recognize the possibility of other explanations."

Dr. Wecht and Mr. Fisher said they hope the report will result in more funding for forensic science efforts to help ease backlogs of DNA cases, a persistent problem throughout the country.

That DNA evidence is often needed to correct errors caused by less-proven methods.

"One of the effects of advanced DNA has been to point out the flaws in hair and fiber analysis, bite marks and latent prints," Mr. Fisher said.

"DNA has shown us that, to a certain degree, forensic science isn't hard science. It's bonehead science."


Daniel Malloy can be reached at dmalloy@post-gazette.com or 412-263-1731.


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