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Research Needed to Improve Forensics for Criminal Investigations, Experts Say at AAAS

Advances in DNA science have helped exonerate more than 270 people in the United States convicted of crimes they did not commit. But with biological evidence available in only a small percentage of court cases, research is needed to improve non-DNA forensic tools, experts told a recent meeting at AAAS.

DNA testing is being more widely used from the start of criminal investigations, a development that should help reduce wrongful imprisonments, said Kenneth Melson, acting director of the federal Bureau of Alcohol, Tobacco, Firearms and Explosives.

But, he said, “we’re going to have a lot of people in jail for which science will not be able to prove their innocence because there isn’t the biological evidence and there isn’t a type of forensic exam like DNA” that can definitively establish innocence.

“That’s what is magical about DNA,” agreed Joe S. Cecil, head of the program on scientific and technical evidence at the Federal Judicial Center. Other types of evidence, including fingerprints and ballistics, don’t typically provide the same sort of statistical assurance, he said.

Kenneth Melson

Melson and Cecil spoke 14 July at the opening of a two-day meeting of the AAAS Science and Human Rights Coalition, a network of scientific membership organizations that recognizes a role for science and scientists in efforts to realize human rights. They were joined by Sarah Chu, a forensic policy specialist for The Innocence Project, a national litigation and public policy organization dedicated to exonerating the wrongfully convicted.

Mark S. Frankel, director of the AAAS Scientific Responsibility, Human Rights and Law Program, moderated the discussion, which followed the screening of the film “After Innocence.” The film chronicles the stories of eight wrongfully convicted and imprisoned individuals who were later freed with the help of the Innocence Project, mostly through testing of DNA evidence.

Sarah Chu

Frankel asked if there is any way to estimate the potential number of innocent prisoners now in U.S. prisons. “We just don’t know,” Chu said. One of the many reasons it is difficult to estimate this number is because some defendants enter into plea bargains, she said, making it difficult to assess whether there might have been a different outcome had their cases gone to trial. Prosecutors can bring substantial pressure to get pleas, Chu said. Of 27 people who pleaded guilty and later were exonerated by The Innocence Project, 10 of them had been threatened with the death penalty, she said.

Additionally, post-conviction DNA is not available in most cases. “Of the cases that do make it to court, only about 5 to 10% involve DNA evidence. And so the Innocence Project’s reach is very limited in this huge criminal justice system,” Chu said. The 272 people who have been exonerated so far through the use of DNA evidence likely represent “only the tip of the iceberg,” she said.

“I don’t think there is a way to determine how many people in jail are actually innocent,” Melson agreed. “The fact that we’ve had exonerations does show that our criminal justice system is not perfect.” He said it is important for prosecutors and police to review cases where biological evidence is available for re-examination using the latest methods of DNA analysis.

According to Chu, The Innocence Project has received more than 40,000 letters requesting help since it was founded in 1992 by attorneys Barry Scheck and Peter Neufeld at the Benjamin N. Cardozo School of Law at Yeshiva University in New York City. Many cases are not accepted because biological evidence—hair, tissue, fluids—was never available for evaluation or it has been lost or destroyed, Chu said. Over the years, the project has rejected 29,350 cases and now has about 9700 in some stage of evaluation. The project currently has 230 clients and is consulting on 60 other cases.

Chu noted the importance of preserving biological evidence for post-conviction analysis. Congress passed a law in 2004 that provides financial incentives to the states for preserving such evidence. Chu said 48 of the 50 states now have laws granting inmates access to DNA testing (Oklahoma and Massachusetts are the exceptions). But the laws vary in scope, and motions for testing are often denied.

Still, there are efforts underway to redress past wrongs. Melson said prosecutors are more willing to go along with post-conviction DNA testing. “I think the culture has changed tremendously,” he said. He noted that San Diego prosecutors have established a process for examining all past cases in which there was biological evidence.

Whether science will be able to provide other forensic tools with the power of DNA testing remains an open question. DNA testing was developed from fundamental studies on genetics at leading research institutions. According to officials at The Innocence Project, many other forensic methods such as hair microscopy, bite-mark comparisons, firearm tool mark analysis, and shoe-print comparisons have not been subjected to comparable scientific rigor.

“There is a huge opportunity to improve the reliability of non-DNA forensic tools,” Chu said. Melson agreed, citing what he called “a wholesale failure” of academic and research scientists to get involved.

Joe S. Cecil

Cecil, who served on a National Research Council (NRC) panel that reported in 2009 on the state of the nation’s forensic science, said he was “surprised at the lack of communication between the traditional science community and the forensic science community.” Part of the reason, he said, is that many forensic scientists come from a law enforcement environment where the priority is investigating crime. “They didn’t grow up in a research culture,” he said. “These scientists were not part of that tradition of self-criticism and transparency.”

The NRC panel found serious deficiencies in the forensics system, including lack of rigorous and mandatory certification programs for forensic scientists. It found that many labs were understaffed, underfunded, and lacked effective oversight. They often struggle with huge backlogs of crime samples to be tested, Cecil said, leaving little time for practitioners to do research on new or improved methods.

Still, Cecil sounded an optimistic note. “I think we are on threshold of better practice,” he said. The federal government has shown a willingness to fund research on new forensics methods, he said, although Melson noted that the battle over the federal budget deficit does not bode well for a boost in spending. Melson stressed the urgency of improving forensic science after many years of budgetary neglect by Congress and state legislatures. It can provide a basis for the judicial system’s credibility and reliability, he said.

Frankel of AAAS noted that Article 15 of the International Covenant on Economic, Social and Cultural Rights recognizes the right of all to enjoy the benefits of scientific progress and its applications. He asked how that principle might apply in the judicial context.

“Every defendant has a right to make sure that evidence submitted in court meets minimum standards of scientific validity and reliability,” Cecil said. He called it a fundamental requirement in the prosecution of any individual. Judges should turn to the scientific community to make sure that minimum standards of reliability are met, he said.

In turn, Cecil said, scientific organizations have an “affirmative obligation” to help improve the quality of forensics by providing the rigor, analytic techniques, and methodologies that are common in other fields of science.

AAAS offers one resource that can help make a difference. Jessica Wyndham, associate director of the Scientific Responsibility, Human Rights and Law Program, said the “On-call Scientists” initiative—a database of more than 650 scientists and engineers willing to provide their expertise to human rights groups—includes 45 specialists in DNA analysis. Chu said members of the Innocence Network, more than 50 affiliated organizations worldwide seeking to reverse wrongful convictions, are aware of On-call Scientists and several already have requested assistance from the volunteers. Chu suggested spreading the word to appellate lawyers as well.


Learn more about the AAAS Science and Human Rights Coalition.

Learn more about the AAAS Scientific Responsibility, Human Rights and Law Program.