Beside several unsolved slayings from the civil rights era, the Labor Day Murder—the brutal 1990 attack of two senior women after a knock on their door—stands as one of the most infamous in Mississippi history.

Authorities said they now have the man who knocked on a door, and then brutally killed 65-year-old Betty Jones, and raped her roommate, 81-year-old Kathryn Crigler, on the night of Sept. 3, 1990.

Forensic genealogy was again the technique that allowed the breakthrough in the cold case—in this case, the Parabon NanoLabs genealogy program.

Michael Wayne Devaughn, 52, is now held on an $11 million bond in a Mississippi jail, after being arrested and charged on Saturday. He was scheduled to make a first court appearance late Monday.

Chief Frank Nichols of the Starkville Police Department said the major breakthrough was made by Sgt. Bill Lott.

Lott worked at least part of the case on his free time, after the clock on his patrol shift had expired. The sergeant said it was science—and persistence—that made the breakthrough.

“(The chief) didn’t have to let me work on this case,” said Lott of his chief. “I mean, think about it, guys … a 28-year-old murder case and it hasn’t been solved.

“It takes a lot,” the sergeant added.

The unknown killer knocked on the door of the Starkville apartment sometime between 8 and 10 p.m. that Labor Day night. Jones answered the door, and her throat was cut almost immediately, according to authorities. Jones died at the scene.

Crigler, who was in her bedroom, was then raped by the killer, who fled, locking the door behind him.

Crigler had a previous amputation of one leg, according to Lott. But she dragged herself to the kitchen, where she pulled a rotary phone off the wall and asked the operator to call 911.

Police officers who had to break into the residence through a window found Jones dead upon their arrival at the scene. But Crigler was taken to a local hospital, where a full rape kit was taken and sealed.

Crigler died in a nursing home two months after the attack. (Devaughn, 52, is still not charged with her death.)

The semen taken from Crigler’s rape kit produced a full DNA profile in 2005. Over the last several months, the genealogical charts homed in on him as a suspect in the attack.

Lott, who worked Starkville cold cases for several years, quit his job to join the armed forces in Afghanistan, according to the chief. But after a three-year tour, he returned and asked for his old job back. He got back on the force, but with one catch: he had to go to patrol. So Lott worked the case when he got off his shift.

“I felt like the science was our best opportunity,” said Lott, who thanked Parabon.

Parabon has assisted in more than a dozen forensic genealogy “solves” since they announced their program in May. Previously focused on phenotyping—the predictive generation of facial likenesses based off unknown perpetrators’ DNA—the Virginia-based company started working with genealogist CeCe Moore about two weeks after the high-profile arrest of the alleged Golden State Killer in April. Since then, the arrests in notorious cold cases from across the nation have resulted. Last week, it was the identification of an Arkansas man who killed himself during a 1999 police standoff at a Missouri motel, who was identified for three deaths in South Carolina and Missouri in the 1990s.