Rita Curran, 24, was an elementary school teacher in Burlington, Vermont, just starting her career when her life was brutally cut short in July 1971. A roommate found her naked, beaten and strangled. The case eventually went cold and languished for over fifty years. Thanks to DNA and advances in forensics, Curran’s killer now has a name, according to Vermont investigators – William DeRoos.

There will be no justice in court for Curran – DeRoos died of a drug overdose in San Francisco in 1986.

In 1971, he was a 31-year-old newlywed who lived in the same building as Curran. DeRoos’ story was that he and his wife had been together that night and neither had heard anything.

According to CNNone of the first major developments in the case took place in 2014:

A breakthrough in the case finally came in 2014 when a DNA profile was extracted from a cigarette butt found next to Curran’s body, Detective Lieutenant James Trieb said at the news conference. Although the profile was submitted to a national criminal database for DNA, he said, no matches were made. That meant the person with that DNA probably never entered any genetic material into the database, possibly because the person didn’t have a felony conviction.

At a press conference on Wednesday, Detective Lieutenant James Trieb described how he began investigating the case in 2019 and approached Curran’s murder as if it had just happened.

According to his report on the investigation, Trieb discussed the case with detectives and “expert technicians.”

Evidence was tested again, and Trieb said his team used DNA found on a cigarette butt near Curran’s body to do genetic genealogy.

Genetic genealogy is a research method that uses DNA test results to find relationships between individuals and discover ancestral roots. By comparing genetic markers to those of others, genetic genealogy can trace family trees from generation to generation and across continents. In Curran’s case, an expert matched DNA from the discarded cigarette to DeRoos’ relatives on both sides. According to the police report, the expert was unequivocal when he said the killer must be the dead man.

After also finding DeRoos’ DNA on Curran’s torn robe, police questioned his ex-wife again and she admitted lying in 1971 about his whereabouts.

This marks yet another cold case closed by combining DNA and genealogy research, perhaps the most famous of which is the 2018 arrest of Joseph DeAngelo, the Golden State Killer. Since DeAngelo’s arrest, the new field has grown in popularity and public recognition as surprisingly more unsolved crimes have been solved after years of mystery.