Experts say DNA evidence alone may not be enough for convictions
By Tim O'Neiland William C. Lhotka
ST. LOUIS POST-DISPATCH
Tuesday, Feb. 13 2007
Police announce a DNA match in an old murder case. Bingo, says the public.
But how close is "bingo" to conviction?
Perhaps farther than people think, according to prosecutors and defense attorneys who say a DNA match alone may not deliver the goods.
The question arises from the coincidence of having DNA as the foundation of murder charges filed just a week apart in two high-profile and cold cases in St. Louis County.
Both times, DNA matches led to charges against suspects who hadn't been considered before during years of frustrating searches for the killers.
On Friday, a drifter from Vinita Park was arrested in Texas and charged with second-degree murder in the killing of Joyce Belrose, 57, a Webster Groves teacher who was fatally shot next to her SUV in 2000 outside the West County Center.
Des Peres police said routine comparisons with prison inmates' DNA linked a cap found at the murder scene — and scrapings from beneath the victim's fingernails — with Derrick L. Luster, 30.
The Friday before, Gregory Bowman, 55, formerly of Belleville, was charged with capital murder in the 1977 strangulation of Velda Joy Rumfelt, 16, of Brentwood, whose body had been found in southwest St. Louis County.
Investigators said they looked for and found a DNA link between Bowman and semen found on the victim's clothing, after he posted bond while awaiting a retrial in two killings in Belleville in 1978.
St. Louis County Prosecuting Attorney Robert P. McCulloch, who sought the charges in both cases, said officers "have a lot more investigating to do" in the case against Bowman. Detectives are doing the same with Luster.
Norman Gahn, a prosecutor in Milwaukee who is regarded nationally as an expert in DNA-based criminal cases, said Monday through a spokeswoman that he does not know of any murder or rape conviction based solely on DNA evidence.
He doubted such a conviction was possible. Gahn was in trial in northern Wisconsin and unavailable to speak directly on Monday.
His reputation was confirmed by a national figure on the other side — Peter J. Neufeld of New York, co-director and co-founder of the Innocence Project, which has used DNA evidence to exonerate people previously convicted of crimes.
"There have been cold-hit DNA convictions," suggested Neufeld, a defense lawyer. "But DNA retesting tells you whose biological evidence you have. It doesn't tell you how it got there, or when it got there."
If prosecutors have more than DNA to hold against Luster and Bowman, they have not announced it. Police certainly will look for other evidence, but the trail in Luster's case is almost seven years old, and in Bowman's is almost 30.
Prosecutors consider DNA evidence a giant leap for forensic science. Said St. Clair County State's Attorney Robert Haida: "When you have a match in DNA, it's better than anything else. In the post-O.J. Simpson world, that is the kind of evidence jurors want to hear."
Indeed, some courts have noted what lawyer calls "the CSI effect," meaning jurors tend to expect fancy science, like what they see on the TV crime shows.
But juries aren't always wowed by DNA.
In a St. Louis County case in 1992, a jury convicted a serial rapist defendant on 12 counts in which a DNA match was corroborated by additional evidence but acquitted him of 27 counts that rested on DNA alone. The jurors' foreman told a reporter they just didn't think it was enough by itself.
Joseph L. Green, a St. Louis criminal defense attorney who gives seminars nationally on DNA evidence, said juries must examine "the circumstances under which the DNA was found, assuming the collection and testing are valid.
"The question becomes: Why would it be there? Is there an innocent explanation for it?" said Green. But he also said a defendant could be in trouble without some plausible explanation.
Before trial, Green said, defense attorneys must examine how the DNA was taken and processed. If it comes from an old case, he said, "the collection process may not have been sufficiently performed to meet today's standards."
DNA has come a long way in the 15 years since Green and his colleagues used the tactic of challenging the credentials of forensic experts.
"It is changing constantly, or at least on a semiannual basis," Green said. "It has become more efficient and more detailed," in part because of the work of Washington University scientists on genetics.
Jack King, a lawyer and spokesman for the National Association of Criminal Defense Lawyers, in Washington, said DNA "has gotten so much more reliable over time. It's very solid. But there's the human factor. There is always human error, such as mislabeling a sample. The prosecution still has to show that DNA is evidence of homicide."
Susan W. McGraugh, a criminal law professor at St. Louis University, said there is a lingering question of whether DNA alone can sustain a conviction.
"Hypothetically, yes," she said. "But you would certainly want more."
Robert Patrick and Nicholas J.C. Pistor of the Post-Dispatch contributed to this report.