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Can forensic science be trusted in courts? Niewiandomski

The dean of the UCLA School of Law will be in Rochester this week to bring more attention to what she and many others consider a serious problem in the judicial system - faulty forensic science.

Jennifer Mnookin says it's a factor in half of the known cases of wrongful conviction.

"That doesn't mean forensic science is wrong half the time. Let me be clear about that," Mnookin said. "But in the cases where we know we got the wrong answer and we go back and say, 'where were the problems?', faulty forensic science is one of the contributing factors in about half of the cases. It's second only to erroneous witness identification."

Not all forensic evidence is being called into question. For instance, DNA evidence is considered valid and has been a key factor in the exoneration of wrongfully convicted defendants.

At the other end of the scale is one of the more problematic types of evidence, according to Mnookin: bite mark identification.  In between is a variety of pattern evidence, such as fingerprint and firearms identification.  There have been some studies attempting to assess how accurate they are, but Mnookin says there haven't been nearly enough.

Why do courts allow such evidence? Mnookin believes the power of precedence is the answer.

Some types of evidence, such as bite marks and firearms identification, have been used in courts since the early 1900s, Mnookin says judges are reluctant to exclude or radically change what has been allowed in legal cases for a century.

Since the publication of two major reports that examined forensic science in 2009 and 2016 found significant concerns with pattern identification evidence, Mnookin says a few judges have excluded these kinds of evidence and others have required more careful descriptions by expert witnesses. 

But Mnookin says much more needs to be done. She wants to see a national commission of leading scientists, practitioners, and policy makers take on the issue.

"If we can't bring back some kind of national location for engaging around the future of forensic science I think the chances for substantial improvements in these fields and substantial improvements in the way the courts are handling these fields grows significantly dimmer," Mnookin said.

The administrator of the Monroe County Crime Lab says he agrees with Mnookin that more forensic research is needed.

"Certainly nothing is perfect," John Clark said. "We can always stand to improve it a little bit more, so I welcome a lot more research in all the areas of forensic science because that's what science is all about: continuing to improve and updating our technology."

Clark said the local crime lab analyzes DNA and firearms evidence, and does drug analysis on a daily basis. He acknowledges that the lab is not set up as a research facility and some kinds of evidence could use more research.

"And that's just because areas like bite marks and blood spatter, they aren't used very much," Clark explained. "They're not an everyday occurrence that takes place in the crime lab."

Jennifer Mnookin is presenting a public lecture at the University of Rochester's Rush Rhees Library on Tuesday, March 26 from 5 to 6 p.m.

Click on the LISTEN link above to hear an interview with Mnookin.

Beth Adams joined WXXI as host of Morning Edition in 2012 after a more than two-decade radio career. She was the longtime host of the WHAM Morning News in Rochester. Her career also took her from radio stations in Elmira, New York, to Miami, Florida.