AUSTIN (KXAN) — Tuesday marks 25 years since four teenage girls were murdered in a North Austin yogurt shop.

The “I Can’t Believe It’s Yogurt” Shop on Anderson Lane went up in flames on Dec. 6, 1991. When the fire was put out, the bodies of 13-year-old Amy Ayers, 17-year-old Jennifer Harbison, her 15-year-old sister Sarah, and 17-year-old Eliza Thomas were found in the torched building — tied up, stacked on top of each other and all shot in the head. There was also evidence they had been sexually assaulted.

“You can’t help but relive those images and I still see the images,” said former Austin firefighter Rene Garza.

After a quarter of a century, he recalls the exact moment the scene went from a fire investigation to a quadruple homicide.

“The firefighter with me tapped me on the shoulder and pointed down and he asked me, ‘Is that a body?’ And I had to step back,”‘ said Garza. “It was and I saw another body. I knew that it wasn’t right. Something was not right,”

Amy’s brother was home in bed when police officers showed up at their door that night. “I heard my mom scream,” said Shawn Ayers. “I walked in the living room. She looked at me and said, ‘Amy’s dead.’ I mean, play that over in your mind time and time again.”

Eight years later, four men were arrested, but only two — Robert Springsteen and Michael Scott — went to trial. Both men confessed and were convicted, but were both set free when new testing revealed DNA from a mystery suspect was found on the youngest victim, Amy.

“We have some unanswered DNA questions that we are continuing to address,” said Detective Jay Swann with the Austin Police Cold Case Unit.

Det. Swann said the DNA is a very specific type, and finding a match is extremely labor intensive.

“We have to just take a DNA sample from the next person that we think it could be,” said Det. Swann. “And so if we ever get to the point where we have a national database for some of the different sub-types of DNA that we have, that could be one of the keys to bringing this investigation back into the courtroom.”

KXAN asked if any yogurt shop evidence was impacted with the recent problems and closure of the Austin Police crime lab.

The detective said “no,” it’s all been tested by other labs, including the Department of Public Safety.Alicia Inns is live with interviews with the firefighters who were on the scene 25-years-ago.