- Oops!Something went wrong.Please try again later.
For nearly 50 years, no one knew what happened to Teree Becker.
She was last seen Dec. 4, 1975, hitchhiking to see her boyfriend in Brighton, Colorado. Two days later, her body was found dumped in a field outside Denver.
Two passing motorcyclists discovered Becker in the area of 100th Avenue and Lowell Boulevard in Westminster, about 10 miles north of Denver, along with her clothes and personal items, local police said.
An autopsy determined she had been raped and died by asphyxiation, the Westminster Police Department said.
Over the past five decades, investigators have returned to the case again and again. Finally, 48 years later, the mystery of her killer has been solved thanks to DNA technology and genetic genealogy.
He was identified as Thomas Martin Elliot, a career criminal who spent much of his life in and out of prison. He died by suicide in October 1991, at age 40, police said.
How investigators homed in on Elliot
DNA from an unknown male was extracted in 2003 from a piece of evidence in Becker's case in connection with the rape, and an unknown male profile was generated, police said.
The profile was entered into CODIS — the FBI’s Combined DNA Index System.
However, there was no match. Then, in 2013, a match emerged — an unknown male DNA profile Las Vegas police filed in connection with a 1991 cold case involving a female who had been found raped and murdered in her apartment, authorities said.
Based on the DNA link, investigators determined the person who murdered Becker had also murdered the female in the Las Vegas case.
Then investigators turned to genetic genealogy in 2018 — a process that uses DNA to create a family tree and find potential relatives.
That process — led by the Colorado Bureau of Investigation, the genetic DNA lab Parabon Nanolabs and the Denver genealogy company Solved By DNA — lasted five years, finally leading to the identification of Elliot as a suspect.
Westminster police said tracing Elliot’s genetic DNA was "a challenge," as his parents had divorced and he was adopted by his stepfather, whose last name he used.
Years in and out of prison
Westminster police said Elliot had spent "a large portion of his life" in and out of prison.
Before Becker's 1975 murder, he committed a burglary in Lakewood, Colorado. He was convicted and spent six years in prison.
He moved throughout the corrections system and was released from prison in Las Vegas in 1981. After his release, he “proceeded to commit a crime against a child” and was sentenced to 10 more years behind bars, police said.
He was released again in Las Vegas in 1991, then committed the Las Vegas apartment murder police used to create his DNA profile.
“Not long after this homicide, for unknown reasons, Thomas Elliot committed suicide on October 30, 1991,” police said.
Closure for the family of a 'free spirit'
Becker had grown up in Casper, Wyoming, and after she graduated from high school, she moved to metropolitan Denver.
Her family described her as a “free spirit” who enjoyed living life “on the edge,” police said. She was remembered as being able to "hold a conversation with anyone" and enjoying painting and listening to music.
"We are thrilled we were able to solve this cold case and hopefully bring closure to the friends and family of Teree Becker," Westminster police said.
This article was originally published on NBCNews.com