AUSTIN, Texas — For years, the unsolved killings of four teenage girls in an Austin yogurt shop in 1991 haunted investigators in the Texas capital.

Two men were charged and convicted, only to have DNA evidence exonerate them, leaving the brutal deaths — in which the girls were bound, gagged and shot before the building was set on fire — an enduring mystery.

Then Friday, authorities announced DNA evidence identified a new suspect: Robert Eugene Brashers, a long dead serial killer linked to several deaths and rapes across the country.

Austin police say they will provide more details Monday of the breakthrough in the cold case, which was the subject of an HBO documentary series released last month, “The Yogurt Shop Murders.”

Here’s what you need to know:

The victims

The killings happened on Dec. 6, 1991, at an “I Can’t Believe It’s Yogurt!” shop in Austin.

Around closing time, investigators say, someone entered the store through the back door and attacked four teens before setting the building on fire.

Amy Ayers, 13; Eliza Thomas, 17; and sisters Jennifer and Sarah Harbison, ages 17 and 15, had their hands tied with underwear and their mouths gagged with cloth. They were each shot in the head, their bodies found by firefighters battling the blaze.

The wrongly accused

Eight years passed before police made an arrest in 1999.

Robert Springsteen and Michael Scott had been teenagers at the time of the murders. They initially confessed, implicating each other.

They were tried and convicted, even though as they recanted and said their statements were made under duress.

More years passed. The convictions were overturned on appeals. The two men were set for a retrial, but prosecutors said new more advanced DNA analysis pointed to another suspect. A judge ordered both men freed in 2009.

The serial killer

Brashers died in 1999 when he shot himself during an hourslong standoff with police at a motel in Kennett, Missouri.

In the years after his death, police were able to use advances in forensic DNA analysis to connect him to a string of unsolved killings.

In 2018, Missouri authorities implicated Brashers in the 1998 killing of Sherri Scherer and her daughter, Megan, in their home near Portageville, about 155 miles (250 kilometers) southeast of St. Louis. In that case, police said Brashers sexually assaulted the 12-year-old victim.

The police investigation also connected him to the 1990 killing of Genevieve Zitricki, a 28 year-old found beaten and strangled in her bathtub in Greenville, South Carolina, as well as the rape of a 14-year-old girl in Memphis, Tennessee in 1997.

Authorities at the time said Brashers’ lengthy criminal record included attempted murder, burglary and impersonating a police officer.

Killer’s daughter reacts

Brashers’ daughter, in interviews with local news stations, expressed surprise and sorrow upon learning about the latest deaths linked to her father.

Deborah Brashers-Claunch told KVUE-TV that she was just an infant when the Austin murders happened and just 8 years old when her father died.

She told KXAN-TV that she didn’t know why he ended up in Austin, other than to note that he worked in construction. She said she believes more crimes could come to light.

“I am very sorry to every family that my father hurt,” Brashers-Claunch told the Austin station. “I know that it is not my place at all to tell you I am sorry, but someone has to because he was not sorry for it and half of my DNA is the person that hurt you the most, so I want to tell you sorry, and I am so sorry for everything. But I am finally glad that you are getting answers.”