After DNA Database Correction, Travis County Preps for Review of Cases

Oct 28, 2015

District Attorney Rosemary Lehmberg announced last week that hundreds of criminal cases in Travis County could be subject to appeal because of a change in DNA standards. Initially estimated in the hundreds, the number of cases has begun to look much higher, with anywhere from 4,000 to 5,000 cases that may be up for appeal.


The District Attorney’s Office says they’ve already notified some inmates sitting on death row that their case may be subject to appeal. So, what’s to blame for this mountain of cases that will have to be reviewed? Assistant District Attorney Robert Smith says one reason has to do with an FBI database that spits out statistics when you’re looking at a piece of DNA.

Smith says the Combined DNA Index System database, known as CODIS, supplies a probability in each case – whether the DNA submitted belongs to a defendant, or somebody else.  Smith says it turns out those probabilities were off by a little and that it’ll affect cases going all the way back to 1999, when the database error occurred.

Smith says this is the lesser of the two issues affecting the cases.

“It used to be with DNA, we would just show up and there’d be a big pile of blood, and it would be one person. Now it’s getting more into touch DNA, where we’re swabbing steering wheels, and we’re finding two or three people who might’ve been suspects in the case,” Smith says.

That results in a mixture of DNA, he says, but, when you test it, there are peaks. So, if a suspect’s DNA shows up and hits a certain threshold, the standards would identify the suspect – if they touched the steering wheel or the doorknob, in Smith’s example.

But the Texas Forensic Science Commission is now saying that this threshold needs to be higher, which brings into question another slew of cases.

The commission is impaneling a group of both scientific and criminal justice experts to address “challenging forensic problems such as those inherent in DNA mixture interpretation,” the agency said in a letter addressing the amended threshold and the FBI’s correction to its database.

Travis County says it will have to hire additional attorneys and paralegals for its Conviction Integrity Unit to review the cases. Officials are not yet sure how much that’ll cost.