Teen Kim Bryant was killed in 1979. Now DNA has helped identify a suspect.

More than 40 years after a teenage girl's murder in Las Vegas, her suspected killer has been identified through DNA evidence and genetic genealogy.

Kim Bryant, 16, was kidnapped, raped and killed on Jan. 26, 1979, police in Las Vegas said.

The teen was last seen at a Dairy Queen restaurant near her high school and was reported missing after she didn't return home, police said.

Her body was found one month later in a desert area, police said.

For decades, her slaying went unsolved.

Semen from a suspect was recovered during Bryant's autopsy, but the DNA sample could not be identified at the time, Las Vegas Metropolitan Police Lt. Raymond Spencer said at a news conference on Monday.

"We first attempted DNA on this particular case back in 2008. We were not able to get a DNA profile," Kimberly Murga, director of laboratory services for the Las Vegas police, said at the news conference. "Technology has continued to advance and revolutionize. We again attempted DNA on different items of evidence in January of this year. We were able to obtain a foreign male DNA profile on some evidence and we put that DNA profile into CODIS -- the Combined DNA Index System -- and at that time we obtained no hits."

That's when the department turned to advanced genetic genealogy testing, she said.

Through genetic genealogy, DNA left at a crime scene can be used to identify a suspect's family members, who voluntarily submit their DNA to a genealogy database. This allows police to create a more detailed family tree than if they were limited to using law enforcement databases like CODIS. Genetic genealogy gained visibility as an investigative tool in 2018 when the "Golden State Killer" was arrested.

Employees of Othram Inc., a private laboratory, built a genealogical profile of Bryant's unknown killer through his family tree, Michael Vogen, director of case management at Othram, said at the news conference.

Othram and police eventually narrowed the search to a relative who was willing to give a DNA sample, officials said.

That sample allowed investigators to zero in on their suspect, Johnny Peterson, who died in January 1993, police said.

Peterson was 19 and living in Las Vegas at the time of the murder, Spencer said. Peterson had previously attended Bryant's school, though it's not clear if they had interacted, Spencer said.

In April 1980, Peterson was arrested for sexual assault, but that case was dismissed, Spencer said.

Peterson was never on the department's radar as a suspect in Bryant's case, Spencer said.

For Bryant's family, Spencer said, "Nothing is gonna make the pain go away, but at least the family has some closure."