By Peter Rossi, LAW WEEK COLORADO
DENVER—There’s a link in the recent cold-case, first-degree murder convictions of Diego Alcalde and Kevin Elmarr: Colorado Bureau of Investigation DNA expert Yvonne Woods, who tested DNA and testified at both Boulder County trials.
Alcalde was convicted of murdering former University of Colorado student Susannah Chase in 1997. He used a baseball bat to beat her before raping her. Elmarr was convicted last week of first degree murder for the 1987 killing of his ex-wife Carol Murphy.
In the Alcalde case, Woods, who declined to comment for this story, testified that Alcalde’s DNA matched that found inside Chase. And she explained it in simple terms for the jury.
“She’s a very brilliant scientist who’s able to explain this complicated DNA technology to the average person without a scientific background,” said Boulder First Assistant District Attorney Ryan Brackley, Alcalde’s prosecutor. “She took a known sample from the defendant, she ran it and got a DNA profile, which matched work done by others.”
That other testing was done by the CBI’s Ron Ardt as well as a private lab.
In the Elmarr trial, Woods’ testimony proved equally crippling to the defendant’s case.
Woods and the CBI performed an “exclusion calculation” to determine the killer. Such a calculation is performed when more than one specimen is inside the victim. Because her then-boyfriend had sex with her two days before the murder, his DNA was present, too.
The calculation was essential because prosecutors wanted to prove that Elmarr had sex with her on the night of the murder and that the boyfriend did not. The test excluded 99.999998 percent of the population of having sex with her on the night of the murder, but not Elmarr, said prosecuting attorney Bruce Langer.
“She showed Elmarr must have had sex much more closely in time than the other guy,” Langer said.
Elmarr denied having sex with her, but the test proved that stance wrong.
Solving two cold cases in the same judicial district within a couple of months is unique, but prosecutors agree that the advancement of DNA technology will continue to solve such cases.
“There’s also a certain expectation from the public that if this technology is available, it will be used,” Brackley said.
Langer agreed. “There is a rush of cases being solved because they’re applying the new technology.”