The murder of a Vermont teacher over 50 years ago was solved after a discarded cigarette butt was linked to a suspect.

Using genetic genealogy police linked William DeRoos to the crime. Right after the murder, DeRoos left the U.S. to become a Buddhist monk the Burlington Police Department claimed Tuesday.

DeRoos died in San Francisco 15 years after Rita Curran, 24, was strangled Acting Burlington Chief of Police Jon Murad explained.

“The random violence of her murder left a stain on our community, and it devastated her family,” Murad said. “For 50 years they have waited for justice.”

After more than 50 years, the murder of 26-year-old Rita Curran has been solved. Curran was found dead in her apartment on July 19, 1971, by her roommates. And the evidence was collected at the scene. Most importantly a cigarette butt found near her body was preserved.

In 2014, the cigarette butt was submitted for DNA processing. A male DNA profile was developed. Unfortunately, the DNA search did not return any matches at the time. And the case went unsolved for several more years.

Fast forward to today, with the advances in DNA technology, the case has finally been solved. Using DNA testing and genetic genealogy, police are closing the 1971 cold case murder.

The police worked with Parabon NanoLabs, a genetic genealogy firm, to search publicly for clues about the killer's identity. 

Within a few hours, they were able to narrow the list of potential suspects to William DeRoos, also known as "Dutch." He lived in the same building where Curran lived.

The suspect becomes a Buddhist monk in Thailand 

After interviewing DeRoos's then-wife, Michelle, detectives discovered that on the night of the murder, the couple had gotten into a fight. DeRoos left home and returned after his wife was asleep. He told her to tell authorities that they had been home all night. Michelle was unaware of the murder in the building and kept her husband’s alibi.

After the murder, DeRoos left his wife and moved to Thailand to become a Buddhist monk. He returned to the United States in 1974 and settled in San Francisco, where he married another woman. 

She told authorities that "Dutch," could be violent. He once choked her and stabbed a friend with a knife in an unprovoked assault. He was arrested for the stabbing. But there is no record of charges being filed. He died of a drug overdose in a San Francisco hotel in 1989.

Additional DNA testing found a sample strongly associated with DeRoos’s DNA on a jacket Curran had been wearing the day of the killing. While no charges will be filed, the local state's attorney said the investigation found probable cause that William DeRoos committed the murder.

Curran’s parents died before ever finding out who killed their daughter. Her siblings are grateful that detectives solved the cold case. 

Rita Curran was murdered only two weeks after moving out of the family’s home for the first time.

“I don’t think so much about the guy who did this as I do about Rita and my parents and what they went through,” said her brother, Tom Curran. “I pray to my parents, and I pray to Rita.”