Congress Probes Science Behind Convictions A recent study questions the scientific validity of many forensic techniques routinely used in criminal prosecutions. Lawmakers at a Senate hearing on Wednesday asked whether people have been put to death for crimes they didn't commit based on these techniques.
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Congress Probes Science Behind Convictions

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Congress Probes Science Behind Convictions


Congress Probes Science Behind Convictions

Congress Probes Science Behind Convictions

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  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
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Members of Congress on Wednesday appeared likely to allocate money for more research into forensic analysis. Senators at a hearing on strengthening forensic science also seemed to support creating national standards for crime labs and forensic analysts, in light of a report that questioned the validity of many long-established forensic techniques.

Forensics have been a central part of the criminal justice system for decades. Defendants are regularly convicted of crimes based on analysis of fingerprints, hair samples or blood spatters from a crime scene. Some defendants have been executed based on such evidence. But a recent report by the National Academy of Sciences said many of those techniques have never been scientifically tested.

That report "is one of the most important developments in forensic science since the creation of the first crime laboratory in the 1920s," Case Western Reserve professor Paul Giannelli told the Senate Judiciary Committee.

Sen. Al Franken (D-MN) called the report's conclusions "damning" and "terrifying."

Little Science, Few Standards Behind Techniques

The two-year study commissioned by Congress concluded that DNA analysis is the only forensic technique that has been scientifically proven to connect crime scene evidence to a defendant. Everything else, from ballistics to burn marks, is uncertain.

"Our criminal justice system, particularly in the most serious cases, has to be based on facts," said committee Chairman Patrick Leahy (D-VT).

He noted that 1 in 5 labs does not meet accreditation standards set by the National Academy of Crime Lab Directors. "We cannot allow these nationwide deficiencies in forensic sciences to continue," Leahy said.

The report also said there are no national standards for the people who perform forensic analysis. For example, one fingerprint analyst may declare a match if he can identify six points in common between a crime scene print and a defendant. Another analyst might require 14 common points to declare a fingerprint match.

Sen. Jeff Sessions (R-AL), the committee's ranking member, found the conclusions difficult to swallow.

"I don't think we should suggest that those proven scientific principles that we've been using for decades are somehow uncertain," said Sessions.

The problem, according to the report, is that many forensic principles are neither proven nor scientific.

Bad Science Behind Convictions

At the hearing, witness Peter Neufeld, director of the Innocence Project, introduced a guest: Roy Brown, who was convicted of murder based largely on testimony from a forensic dentist. Brown sat behind Neufeld in the hearing room.

"The forensic dentist [at Roy Brown's trial] used what was then the prevailing method of comparing bite marks found on a body with the dentures of a suspect," said Neufeld. "He examined them and decided that he had a match with Roy's bite. He so testified in court, and Roy was convicted."

After Brown spent 15 years in prison, DNA evidence identified the real killer.

Neufeld said bite mark analysis is just one of many areas that remain untested.

"And they need more research, basic research, applied research. They need standards like DNA has," Neufeld said.

He testified that the Innocence Project has exonerated 242 prisoners, 17 of whom were on death row.

Franken replied that in the face of such strong evidence of flaws in the justice system, a punishment as irreversible as the death penalty is, at the least, "problematic."

Prosecutors at the hearing testified that defense lawyers are already using the forensics report to challenge convictions.

"This is true even though the report made efforts to say that no judgment is made about past convictions," Alabama prosecutor Barry Matson said.

"Have regrettable instances occurred in the forensic setting? Yes. Is it to the level that some entities and special projects would have us believe? Absolutely not," Matson said. "As long as human beings are involved, we will endeavor to do the very best we can, but no system we ever have will be perfect."

Call For Standards

No one at the hearing objected to further research into forensic techniques. There also seemed to be consensus that federal standards should exist for crime labs and for analysts. Members of both parties supported federal funding to train forensic scientists.

Other proposals were more controversial.

The report by the National Academy of Sciences recommends creating a national government agency to oversee forensic science. Prosecutors resisted that idea, and Sessions said the federal government shouldn't "try to micromanage every burglary, robbery and rape case" in America.

Some Democrats suggested that the flaws identified by the forensic science report necessitate a moratorium on the death penalty, but that suggestion had little support from conservatives in the room.

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