2015/09/15

The Texas Tribune September 12, 2015: New Protocol Leads to Reviews of "Mixed DNA" Evidence

This past spring, the FBI notified crime labs there were errors in the data used to calculate the chances that DNA found at a crime scene matched an individual. But it downplayed the impact of the errors on court cases, setting off a low but distinct rumble throughout the criminal justice system nationwide.

After reading the FBI's notice, district attorneys like Galveston County's Jack Roady asked DPS to reassess evidence that had already been tested for use in upcoming trials — this time, using the FBI's corrected data, which was related to population statistics.

"When the FBI sent out the 'pop stat' issue memo, that these were some errors and should not be any issues, I don't have any reason to think they were wrong in that," Roady said.

But a second concern emerged after Roady got his evidence analysis back from one of the eight Texas Department of Public Safety crime labs that tests DNA evidence. Recently, DPS and crime labs nationwide have switched to a more conservative analytical approach when looking at "mixed DNA" — which refers to when more than one individual's DNA is present on evidence. more