(NewsNation) — A nearly 30-year-old cold case has finally been solved thanks in part to a tiny smudge of DNA found on a napkin.

Jerry Westrom, 56, was found guilty Thursday of first-degree premeditated murder and second-degree intentional murder for the killing of 35-year-old Jeanne “Jeanie” Childs.

“My condolences go out to the victim and her family. They have had to live without justice for her brutal murder for nearly three decades. I hope this brings some closure to them,” Hennepin County Attorney Mike Freeman said in a press release.

Childs, who was a known sex worker, was found stabbed to death in her Minneapolis apartment back in June 1993. The crime scene was covered in DNA evidence, but technology could not trace it back to anyone at the time.

For 27 years, the case stayed stagnant, with no luck in proving Childs’ killer.

Then in 2018, investigators checked to see if DNA found at the scene matched any on a “commercial genealogy site,” similar to methods used in the Golden State killer case. Westrom came back as a match.

A self-claimed Minneapolis farmer, officials said Westrom had several run-ins with the law, including involving prostitutes, around the time of Childs’ murder.

Investigators began tailing Westrom in 2019. While he was attending a hockey game with his daughter, he threw out napkins he used to clean his face after eating a hot dog.

Investigators dug the napkins out of the trash and were able to match DNA samples to the ones from the murder scene decades earlier.

Once the connection was made, Westrom was arrested and charged with second-degree murder, which holds a maximum sentence of 40 years if found guilty.

Westrom was later indicted in June 2020 for first-degree murder, which if found guilty carries a mandatory life sentence under Minnesota law.

After just two hours of jury deliberation on Thursday, Westrom was found guilty and convicted of both charges in the killing of Childs.

Westrom now faces an automatic life sentence, without the possibility of parole. However, an official sentencing date has not been released.