http://www.post-gazette.com/local/c...-in-Wolfe-sisters-deaths/stories/201403070121
In an affidavit supporting the arrest Wednesday of Wade, 43, for the killings of Sarah and Susan Wolfe, his next-door neighbors on Chislett Street, police wrote that there was a mixture of DNA from a male and female under Susan Wolfe's fingernails.
Wade, the affidavit said, "cannot be excluded as contributor to this mixture," according to the Allegheny County medical examiner's forensic laboratory division.
Neither the county crime lab nor the district attorney's office would expand on that statement.
It could be telling that Pittsburgh police have retained a local company, Cybergenetics, that specializes in analyzing DNA mixtures from more than one person, to run the evidence through its TrueAllele computer analysis.
The analysis, pioneered by Cybergenetics in Oakland, has been used in various hard-to-solve cases. It can take mixtures of DNA and conclusively identify -- or exclude -- a suspect, and do so more reliably than older DNA technology.
The phrase "cannot be excluded" appears often in criminal cases and hints to defense attorneys that they might have an opening to raise questions about the quality of the DNA match, veteran defense attorney Patrick Thomassey said.
"That tells me that it's a mixture of things and I don't think it's that strong," said Mr. Thomassey, who estimated that he has worked on about 100 cases involving DNA evidence but is not involved with the Wolfe case. "That 'cannot be excluded' phrase is troublesome to the district attorney."