Lexington Herald-Leader

Posted on Sat, Mar. 25, 2006



The Kentucky Supreme Court's decision to throw out forensic evidence in the Shane Ragland murder case underscored the challenges judges face in screening complicated evidence and ever-changing scientific opinions, legal scholars said yesterday.

Judges act as gatekeepers for scientific evidence, charged with throwing out unreliable or "junk" science and accepting sound evidence that could help jurors.

It's a task that's even more complicated than it sounds, given that judges must also comply with higher court precedents -- which, like the science they're evaluating, are complicated and ever changing.

"It is among the toughest things judges have to deal with," University of Kentucky law professor Robert Lawson said. "The lawyers are great at this. They go out and get an expert and they portray him as the smartest, most experienced, most highly recognized person in the world. ... He will paint a picture of the evidence that is so beautiful and so persuasive.

"The judge has to look at it and say, 'Is this a bunch of junk?'"

On Thursday, the high court overturned Ragland's 2002 murder conviction in the slaying of University of Kentucky football player Trent DiGiuro, 21, a walk-on offensive lineman. The 5-2 majority said FBI tests, called comparative bullet lead analysis, used to link Ragland to the slaying were based on unreliable science.

Lawson said the CBLA decision is a prime example of the way that scientific consensus can change over time.

FBI abandoned test

When Circuit Judge Thomas Clark allowed prosecutors to present the tests in 2002, a nationwide assault on CBLA by defense attorneys and metallurgists was just picking up steam.

At the time, the FBI stood solidly behind the analysis. By 2005 it had abandoned it.

The FBI had used the analysis in 2,500 cases since the early 1980s, mostly in cases where a gun is not recovered or a bullet is severely misshapen. The analysis was introduced at trial in less than a fifth of those cases.

It's not known how many Kentucky cases it was used in. The test was also used in Ronnie Lee Bowling's trial over the slaying of two gas station attendants in Laurel County.

The lead in bullets is derived from recycled batteries, which contain several trace elements, including arsenic, bismuth, copper, silver and tin. The FBI long thought that different batches of bullets contain slightly different compositions of those elements. So, two bullets with the same composition would be from the same batch.

Using highly sensitive instruments, the FBI crime lab determined that bullets found at the scene of DiGiuro's shooting had the same composition as those seized from the two homes of Ragland's divorced parents, and thus could have come from the same batch.

But Vince Tobin, formerly the FBI's chief metallurgist, has refuted several of the agency's assumptions. He testified in Ragland's case that bullets from different batches can have the same composition.

Triggered in part by Tobin's criticism in other convictions, the FBI commissioned a report by the National Academy of Sciences.

The academy found the tests unreliable, and in September 2005, the FBI stopped conducting them. It said "neither scientists nor bullet manufacturers are able to definitively attest to the significance of an association made between bullets in the course of a bullet lead examination."

After that development, the Supreme Court had no choice but to overturn Ragland's conviction, Lawson said.

"It would have been shocking, I think, for the court not to reverse that," he said.

Prosecutors have said CBLA methodology is sound, and jurors should decide how to interpret it.

The prevailing standard

The seminal case for evaluating scientific evidence is Daubert vs. Merrell Dow Pharmaceuticals Inc., in which the U.S. Supreme Court ruled that expert testimony must be based on a testable theory or method that has passed peer review, has a known error rate and has reliable results.

The 1993 ruling was one of the cases cited by the Kentucky Supreme Court in the Ragland opinion.

UK law professor William Fortune said the opinion created a more flexible standard over a previous precedent that barred theories not generally accepted by scientists. That prevented juries from hearing new and developing theories, he said.

But Lawson and Fortune say it also brought more scrutiny to scientific evidence by expressly charging judges as guardians against bad science.

"Courts had tended to say, 'OK, we'll let it in,'" Lawson said.

In part, the Daubert ruling was triggered by the proliferation of professional witnesses who based their opinion more on who wrote their paycheck rather than on sound science, Lawson said.

Daubert allows parties to request a hearing in which the judge listens to and questions expert testimony from both sides. That happened in Ragland's case.

Judges may also call their own, independent experts.

"I think the (U.S.) Supreme Court felt that juries simply were not able to separate the so-called wheat from the chaff," Fortune said. "To ask a jury to make that call was a little much. ... The judge is just better able to do it because he can refer to books, read briefs and all that kind of thing, which is obviously not practicable for jury to do."

Junk Science
Truth in Justice