AUSTIN (KXAN) — A judge decided to not allow certain DNA evidence in the case against Meechaiel Criner, the man accused of killing University of Texas at Austin student Haruka Weiser.
Criner’s defense has been arguing this week that a new software the Department of Public Safety used to analyze DNA evidence is not reliable.
DPS started using the STRmix software in March 2016 and claims it is reliable and able to analyze mixtures of DNA.
DPS employees testified that when more than one person’s DNA is present in a DNA sample, it can be difficult to determine whose is there, so this genetic probability software is used in hopes of getting closer to an answer.
The main pieces of evidence in question were swabs from Weiser’s thigh. The first did not show evidence of Criner’s DNA. A second swab was analyzed by hand and came up inconclusive because the amounts of genetic material were too low.
But when that swab was analyzed using STRmix, the machine said analysts couldn’t rule out the possibility that the DNA was Criner’s.
After hearing both sides of the argument, Judge David Wahlberg ruled Thursday to exclude four pieces of evidence because of procedural problems in the STRmix testing.
The defense explained to KXAN this means excluding two swabs of DNA from Weiser’s thigh that underwent STRmix testing as well as swabs of DNA from her glasses and another from her thigh that underwent a gender-indicator test called Y-STR.
Though the court was scheduled to hear more witnesses this week, the judge felt he had the information he needed by Wednesday morning.
“Essentially the judge felt like he had heard enough, he called us back into chambers, and said, ‘I think I’ve heard enough now, there’s a problem,'” explained Criner’s attorney Ariel Payan.
“There was missing evidence and the judge was upset about that, and there were some procedural problems with what was done and that basically was what was the final straw for the judge,” Payan added.
Weiser was found dead in a creek on the UT campus in April 2016. Her case had been delayed by issues with Austin’s DNA lab.
On the night of her death, Weiser, 18, called a friend to say she was leaving the drama building and on her way home. But Weiser was never seen alive again. Surveillance video, which was not released to the public, showed a man around Waller Creek the night of her death.
According to the affidavit, surveillance video showed a woman walking toward the bridge at Waller Creek, passing by the suspect.
Police say the video shows the suspect put his bike’s kickstand down and reach into the back of his pants with his left hand and pull out what appeared to be a “shiny rigid object.”
The next time the suspect appears on camera he is carrying a small duffel bag that he did not previously have in the video. He also appeared to have an injury to his left leg.
KXAN reached out to DPS with more questions about how they use the STRmix system and why they selected it, but they replied saying they couldn’t comment on this ongoing case.
“However, we are monitoring the proceedings, and we have been in contact with the DA’s office and will provide them any needed information,” a spokesperson for the department replied in an email.
In court, DPS testified that they chose STRmix because there were problems with their old system. They referred to the old system as “CPI” and explained they had complications with implementing it and with handling low-quality genetic profiles.
Current and former DPS employees testified that after an analyst does manual DNA analysis, they export their results into the STRmix software which then spits out the likelihood that the suspect could have DNA in the mix.
The Travis County District Attorney’s office also added that they had no comment at this time.
Testimony in the courtroom explained that there are 31 labs around the country which use STRmix, several internationally, and four DPS labs which do so in Texas.
As this newer technology grows in popularity, genetic probability testing is also seeing more legal challenges across the country. Notably, STRmix results were rejected in a New York murder case in 2016.
“When you have complicated software making decisions about people’s lives, it’s so important that everyone who is interested has access to the software, has access to how those particular decisions are being made,” said Clinton Hughes, a staff attorney with the DNA unit of the Legal Aid Society. Hughes was part of the DNA defense team for the case in New York.
Hughes explained that humans are generally good at identifying individual DNA profiles, but it gets more complicated when more than one’s person DNA is mixed in, which is why more law enforcement departments are looking to genetic probability companies for help. He also noted that STRmix is the most popular of those technologies.
Hughes said that the judge’s decision not to admit some DNA evidence in Criner’s case is a good example of why it’s important to have a hearing before a trial that may involve STRmix evidence.
“So that a judge can hear the evidence, can hear testimony about the evidence before the evidence goes to a jury because this kind of evidence can be very damning before it is proved reliable,” Hughes said.
Jennifer Freidman, the forensic science coordinator for the Los Angeles County Public Defender’s Office, said on June 1 the LA County Sheriff’s Office Crime Laboratory started doing their casework with STRmix.
She noted that the Sheriff’s Office got STRmix validated, but because it’s so new her office hasn’t seen any cases using STRmix evidence yet.
Freidman explained that the vast majority of law enforcement crime laboratories in the country are purchasing software programs like STRmix.
“I expect they are getting more and more pressure from law enforcement and from prosecutors to produce DNA results from everything,” she said. “The reason labs seem to be going in that direction is they recognize they have been making errors and getting inconsistent results when interpreting either complex mixed samples and low template DNA samples.”
Freidman’s office will be closely following STRmix as it continues to be used. They plan to request, examine, and evaluate all of the validation studies of STRMix done by the Sheriff’s Department.
“We also are concerned because STRmix is not an open source program. The algorithm for the software is kept secret, so no one knows exactly how it works and no one knows if there are bugs in the program that could cause errors in a particular type of sample,” she said, adding that she thinks it is “extremely premature” to have people accused of serious crimes to be the first people to experience the impacts of this new software.
Criner’s attorney feels similarly.
“We’re ceding too much of the system to machines. We need to be able to say, ‘hey, a human being ought to be able to explain it or it shouldn’t come in,'” Payan said.
Payan expected to have more time in the pre-trial hearing to explain the defense’s concerns with STRmix testing in general.
“Unfortunately, we didn’t get to a complete challenge of STRmix based upon what happened. We believe that the judge would have excluded the technology because we don’t think its ready for the application it’s being used for,” Payan said. He believes Criner’s case is the first in Texas to successfully challenge STRmix evidence
Criner’s trial is scheduled to begin July 9, jury selection should begin July 2. Payan says he expects the trial to last two weeks, though this decision from the judge may cut down on some of the time both sides would have spent presenting evidence.