Nearly five decades after 16-year-old Corina Lydia Contreraz was found murdered east of Billings, Montana, investigators have officially closed the Yellowstone County cold case. Authorities announced that advanced forensic genealogy and DNA testing successfully identified the man responsible for the 1978 killing.
Corina Contreraz was murdered on Dec. 22, 1978. Her body was discovered by a school bus driver near the intersection of Pryor Creek Road and Indian Creek Road east of Billings. An autopsy conducted that same day revealed she had been sexually assaulted and stabbed 18 times. No arrests were made at the time, leaving the investigation at a standstill for 47 years.
The key break in the Yellowstone County cold case came through a combination of forensic genetic genealogy and an unprecedented source of biological material. While investigators had maintained DNA evidence from the original crime scene for decades without a database match, new avenues opened up. In 2025, investigators utilized forensic genealogy to identify a possible suspect with local ties, later discovering he possessed a criminal history that prompted a search for historical records.
The 1982 Fingerprint Card Breakthrough
Authorities located an old booking fingerprint card from 1982 and submitted it for specialized testing. Lab director Suzanna Ryan of Borealis Forensics explained that usable DNA was successfully recovered from the inked print more than 40 years after the card was archived. Investigators noted that the Yellowstone County Sheriff’s Office believes it is the first law enforcement agency in the nation to solve a homicide by extracting viable DNA from an old fingerprint card—records that were nearly destroyed during state digital archiving transitions.
“We know he touched it, even though the card I worked on was from 1982, so even that many years later that DNA was still present,” Ryan said.
The recovered profile was compared against genetic evidence from the victim’s body. Further family-reference testing confirmed the identification of Angelo James Stallsmith Sr., who was believed to be 29 years old at the time of the homicide. Yellowstone County Sheriff Kent O’Donnell stated that authorities determined beyond a reasonable doubt that Stallsmith was responsible for the sexual assault and death of Contreraz. Investigators noted that Stallsmith died in Billings in 1990 at Billings Deaconess Hospital, and there is no evidence that he and Contreraz knew each other or had previously met. Authorities also confirmed that no murder weapon was ever located.
Family Relief and Moving Forward
For surviving relatives, the identification brings an emotional mix of enduring grief and profound relief. Gloria Flores, a cousin of the victim, remembered Contreraz as a kind, funny, and loving person. Another cousin, Dotty Ramirez, traveled from Ohio for the announcement, recalling her final memories with Contreraz during a birthday celebration just before the tragedy occurred. Ramirez expressed deep gratitude that the truth finally surfaced after nearly five decades of agonizing uncertainty.
Law enforcement officials indicated that the historic fingerprint cards will now be preserved as a vital tool for potential future cold case investigations. With the perpetrator identified and the investigation formally closed, authorities have answered nearly fifty years of questions for the family of Corina Contreraz. Please share your thoughts or comments on this developing story below.
