Influential report casts doubt on nation’s crime labs and forensic techniques

February 19, 2009|By Jason Felch, Tribune Newspapers: Los Angeles Times

LOS ANGELES — For decades, forensic scientists have made sweeping claims about fingerprints, ballistics, handwriting, bite marks, shoe prints and blood spatters that lack empirical grounding and have never been verified by science.

That is just one conclusion of a two-year study by the National Academy of Sciences, which Wednesday called for a wholesale overhaul of the crime lab system that has become increasingly important to American jurisprudence.

The academy, the pre-eminent science adviser to the federal government, found a system in disarray, with labs that are underfunded and beholden to law enforcement, lacking independent oversight and consistent standards.

The report concludes that the deficiencies pose “a continuing and serious threat to the quality and credibility of forensic science practice,” imperiling efforts to protect society from criminals and shield innocent people from wrongful convictions.

With the exception of DNA evidence, the report says many forensic methods have not consistently and reliably connected crime-scene evidence to a specific person or source.

“The simple reality is that the interpretation of forensic evidence is not always based on scientific studies to determine its validity,” the report says.

For example, the frequent claim that fingerprint analysis has an error rate of zero is “not scientifically plausible,” the report said. Regarding bite marks, it said “the scientific basis is insufficient to conclude that bite-mark comparisons can result in a conclusive match.”

Of the 232 people exonerated by DNA evidence, more than 50 percent of cases involved faulty or unvalidated forensic science, according to the Innocence Project.

Margaret Berger, a law professor at Brooklyn Law School and a member of the panel, explained: “We’re not saying all these disciplines are useless. We’re saying there is a lot of work needs to be done.”

Although the panel’s recommendations are not binding, they are considered influential. But the reforms proposed by the academy would take years of planning and major federal funding to enact.

In the short term, a flood of legal challenges — in current cases and convictions that have relied on the techniques — are planned, defense attorneys say. To the frustration of some, the report is silent on how such legal issues should be handled.

The report was hailed by defense attorneys, scientists and law professors, who for years have been raising scientific and legal challenges to the techniques in the courts.

“There are people who have been painted as crying wolf and not taken seriously who have been critics of these techniques,” said Bicka Barlow, a public defender in San Francisco.

———–

Some techniques long suspect

Fingerprint comparisons

For a century, fingerprints went largely unchallenged in the courtroom. But over the past decade, the grandfather of forensic science has seen its reliability questioned and its reputation battered, by both revelations of high-profile mistakes and a lack of uniform standards.

At the same time, there is little if any scientific research to support the claim that no two people share identical fingerprints, a central tenet for those who believe in fingerprint matches.

In perhaps the most stunning fingerprint embarrassment, the FBI was forced to admit that it wrongly linked an Oregon attorney to the 2004 Madrid terrorist bombing case due to an erroneous fingerprint comparison. An international review panel determined that peer pressure inside the FBI crime lab contributed to the error.

The U.S. government later apologized to the lawyer, Brandon Mayfield, and agreed to pay him $2 million to settle a lawsuit.

Bullet-lead analysis

Chemical analysis of the lead in bullets allowed crime lab technicians to compare bullets found at a crime scene to, say, bullets found in the possession of a top suspect.

But such analysis, after in-depth scrutiny, was determined to be flawed and unreliable.

When prosecutors used it to convict Jerry Allen Mark of the 1975 shotgun murders of his brother, his brother’s wife, and their two young children at their Iowa farmhouse, police still considered it good science.

The prosecutors in Mark’s case said they matched the bullets from the murders near Cedar Falls to bullets they said Mark bought in California, where he was living at the time.

In 2006, more than 30 years after the killings, a federal judge awarded Mark a new trial after determining that prosecutors withheld crucial evidence from the defense. But a federal appeals court reversed that ruling in 2007, and Mark remains in a prison in Iowa with a life sentence.

Arson indicators

For years, investigators relied on a series of indicators to help them determine whether a fire was intentionally set. One such indicator: crazed glass, the tiny, weblike lines that spread across glass.

But scientific advances showed those indicators were just myths; in the case of crazed glass, extinguishing the fire produced the lines investigators cited to declare a fire an arson.

In February 2004, Cameron Todd Willingham was executed in Texas for the arson murders of his three young daughters in a fire at their home in Corsicana, south of Dallas.

But a Tribune investigation later that year showed that Willingham’s conviction was based on forensic evidence and arson theories that no longer are considered scientifically valid. The 1991 fire, according to four experts who reviewed the evidence for the Tribune, might have been an accident, not a crime.

Now, in the first state-sanctioned inquiry into a Texas execution, the Texas Forensic Science Commission has asked another expert to review the forensic evidence in the case.

A report is expected in late March or early April.

Bite-mark comparisons

From the start, bite-mark comparison has been a stepchild in the forensic family, even though it has a “CSI”-like appeal, with dentists comparing a suspect’s teeth to a victim’s bite wounds.

But DNA has helped show that bite-mark comparisons are subjective and that even many of the discipline’s founders have, through their work, helped to send innocent people to prison and Death Row.

The brutal 1984 Milwaukee murder case that sent Robert Stinson to prison with a life sentence rested entirely on the controversial discipline. Last month, however, Stinson was freed on bail after a judge vacated his conviction, which hinged on questionable bite-mark comparisons. DNA testing of saliva from a sweater the victim was wearing and a new review of the bite-mark evidence suggested Stinson was innocent.

The Tribune examined Stinson’s case in 2008.

– – –

Fixing the system

Among the recommendations in a report by the National Academy of Sciences:

*Create a federal agency, the National Institute of Forensic Science, to fund scientific research, disseminate basic standards and put control of the field in the hands of scientists who are independent of law enforcement. Currently, much of this work is done by the FBI laboratory and the National Institute of Justice, which the report notes “are part of a prosecutorial department of the government” and “should not be allowed to undercut the power of forensic science.”

*Make crime labs independent of law enforcement. Currently, most crime labs are run by police agencies, and a growing body of research shows that can lead to bias.

*Require that expert witnesses and forensic analysts be certified by the new agency, and that labs be accredited. Currently, these standards are optional.

*Fund research into the scientific basis for claims routinely made in court, as well as studies of the accuracy and reliability of forensic techniques. Those recommendations have been cautiously embraced by leading associations of forensic scientists, which in 2005 helped convince Congress the study was necessary.