“Weak DNA evidence could undermine justice, experts say” @ Chicago Tribune

Posted on July 5, 2012

Steve Mills — July 5, 2012: “When Cook County prosecutors brought Cleveland Barrett to trial earlier this year for the predatory criminal sexual assault of a 9-year-old girl, they presented the jury hearing the case testimony from the alleged victim plus the kind of evidence that long has won convictions with its scientific certainty: DNA.

Indeed, Assistant State’s Attorneys Krista Peterson and Jane Sack told jurors in closing arguments that the DNA obtained from the victim after the alleged incident in July 2010 was a match to Barrett’s genetic profile and evidence that corroborated the victim’s trial testimony.

“Who is the major profile in the DNA that’s found?” Sack asked the jury, according to a transcript from the trial. “The defendant.”

But this DNA was different. It was not from semen, as is often the case in rapes; instead it came from male cells found on the girl’s lips. What’s more, the uniqueness of the genetic link between the DNA and Barrett was not of the 1-in-several-billion sort that crime lab analysts often testify to in trials with DNA evidence. Instead, when Illinois State Police crime lab analyst Lisa Fallara explained the statistical probabilities, she testified the genetic profile from the cells matched 1 in 4 African-American males, 1 in 8 Hispanic males and 1 in 9 Caucasian males.

Fact is, the DNA profile from the cells on the victim’s lips could have matched hundreds of thousands of men in the Chicago region………………..”

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