New DNA Evidence Guidelines Issued in Texas

According to the Innocence Project, Texas leads the nation in exonerations for wrongful convictions that were brought to light through DNA testing technologies. Earlier this year, Texas Gov. Greg Abbott signed a new law that broadened access to DNA testing in those cases where DNA evidence may be able to prove a wrongful conviction.

Most people — most juries — believe that DNA evidence is a sure sign of guilt. After all, if the chances are “1 in a billion” that DNA found at a crime scene belonged to more than one person, odds are that the person was there, right? Not necessarily so, says the FBI.

Earlier this year, the FBI notified crime labs around the country that there were errors in the data used to calculate those chances that DNA found at a crime scene matched one individual. Instead of “1 in a billion”, the chances now are more like “1 in 100” that a defendant was the only source of DNA when examining “mixed DNA” — which is when more than one person’s DNA is present on evidence.

Based on the FBI notification, the Texas Department of Public Safety (DPS) recently notified prosecutors that it was switching to a more conservative analytical approach for mixed DNA analysis and provided a list of 24,468 cases that could be affected by the change.

However, the DPS only operates eight DNA crime labs in the state; local governments operate others. No one has yet grappled with the potential inconsistency in calculations from different crime labs in the state, although both prosecutors and defense attorneys have posed the question to the Texas Forensic Science Commission.

“While in many cases the changed protocols may have no effect, it is also possible changes to results may be considered material by the criminal justice system, either in terms of revisions to the population statistics associated with the case or to the determination of inclusion, exclusion or an inconclusive result,” the commission wrote in an Aug. 21 memo. “The potential range of interpretive issues has yet to be assessed, but the potential impact on criminal cases raises concerns for both scientists and lawyers.”

The Cogdell Law Firm is a boutique law firm focusing on large, complex business and criminal financial-related litigation, including white collar criminal defense, securities fraud, health care fraud investigation, criminal appeals and state criminal defense. When results matter most, contact Dan Cogdell at (713) 426-2244 or