AUSTIN (KXAN) — After 30 years, Austin city leaders announced the infamous yogurt shop murders had been solved. Austin Police Chief of Police Lisa Davis said, “advances in science and technology” allowed investigators to link Robert Eugene Brashers to the 1991 quadruple homicide.
Detective Dan Jackson with APD said that samples of Y-STR DNA found at the scene linked Brashers to another crime in South Carolina.
Y-STR examines short repeating DNA sequences only found in people with a Y chromosome. DNA testing to identify suspects was first used in 1990 in Germany.
Jackson said there are some limitations when using Y-STR for identification. It is not unique to only one individual and is “passed down paternally”. Certain combinations of Y-STR occur more frequently, so you can have multiple matches.
Y-STR is good an eliminating suspects, Jackson said, but not at identifying one person. This is because they are not unique. However, in this case, there was a one-to-one match with Brashers.
So why did it take so long?
Initial DNA testing
DNA testing was primitive at the time of the murders. DNA samples were taken at the time from the victims both at the crime scene and during their autopsies, Jackson said.
In 1999, when four suspects were tried and found guilty for the crimes, DNA evidence was used. By this time, Y-STR testing had come further along. A lab in Fairfax, Virginia developed a Y-STR profile for the crime.
“They were able to get a profile from the sexual assault kit that had 16 markers, 16 locations with genetic data on it, on the Y chromosome, the kit only tests for specific 16,” Jackson said.
All four of the original suspects were excluded from the after the Y-STR profile. In 2009, charges against the four men were dropped.
Hundreds of DNA samples were collected over the next several years.
Search for the right DNA
Only a small amount of DNA was recovered from the crime scene. Jackson said it was several picograms of DNA. One picogram is a trillionth of a gram in size.
In 2018, advances in DNA testing allowed for a new round of testing. This time, scientists were able to find 27 markers in the Y-STR sample. This sample was also found on other swabs from the victims.
In 2022, Detective Jackson spoke with DNA experts.
In July, APD met with detectives working on a case in Kentucky that had a ballistics match with the Yogurt Shop Murders. The Kentucky unit had not done a Y-STR profile on their case. Jackson asked them to do so. He also asked them to search for other Y-STR matches in their DNA database.
“This is not something you can do an automated search like CODIS. It has to be a manual a manual search, because we have tried this once before nationally,” Jackson said.
CODIS, the Combined DNA Index System, is a system managed by the FBI that allows federal, state and local officials to match DNA profiles. While CODIS does accept Y-STR data, according to its website, it only allows searches using this data for “missing person-related indexes”.
From 2018-2019, APD attempted a manual Y-STR search, but few labs were profiling them at the time in CODIS samples. By 2025, the database had grown.
In August, Jackson requested a manual search for all DNA labs in the U.S. that keep Y-STR data. He got a match.
Finding Robert Eugene Brashers
The South Carolina State Lab responded with a match to Jackson’s search. APD said this is the first time the lab got a search request for Y-STR data.
The search revealed Brashers. The Y-STR samples were collected from a sexual assault and murder from 1990. The sample was a one-to-one match with those collected from the Yogurt Shop Murders.
Signature Science, an Austin-based testing firm, found that the sample was rare. It occurred in 0.12% of the U.S. population.
Police tracked Brashers’ movement from 1989 until 1999, when he died by suicide. His DNA was linked to crimes ranging from an unsolved murder in 1990 in South Carolina to a 1998 assault in Tennessee. DNA links Brashers to at least six other cases, according to APD.
Ballistics data from a gun used in several crimes further connects Brashers to those crimes.
Finally, Brashers Y-STR profile was found in sexual assault kits from three of the Yogurt Shop Murder victims.
Final DNA testing of the Yogurt Shop Murders
On Sept. 15, additional samples were submitted for testing to DNA Labs International, based in Florida. While these samples had been tested before they did not meet CODIS quality/quantity requirements.
For a sample to be submitted to CODIS, it must have 20 loci. This is basically a specific, fixed point on a chromosome. A street address that can be occupied by different genes. Samples must have all these street addresses. Before 2016, the FBI required 13 loci in each sample.
STR samples from beneath the fingernail clippings of victim Amy Ayers match Brashers’ STR.
On Sept. 22, DNA in Kentucky was compared to Brashers. It likely matches, Jackson said, but the final report hasn’t been concluded.
KXAN reached out to Signature Science about their involvement. They told KXAN in a statement:
“In accordance with our confidentiality policies and professional obligations, Signature Science does not comment on any specific case without permission from our clients. We remain committed to upholding the highest legal, ethical, and scientific standards in service to our community and clients.”
“As members of the Austin community, all of us at Signature Science extend our heartfelt thoughts to the families of the four girls whose lives were tragically taken. We are grateful to the Austin Forensic Science Department, the Austin Police Department, and the Cold Case and Missing Persons Unit within the Texas Attorney General’s Office for their dedication and persistence in solving this case,” said Leslie Parke, Forensic Laboratory Director, and Brian Schimmoller, President and CEO.
During the press conference, Dr. Dana Kadavy, director of the Austin Forensic Science Department said a simple statement regarding the investigation. “The DNA story never changed.”