(CNN)After 65 years, a grisly double murder case of two teenagers in Great Falls, Montana, was solved with DNA evidence, according to investigators.
"It was such a big case," Cascade County Sheriff's Office lead investigator Sgt. Jon Kadner told CNN Wednesday night. Investigators have determined that the killer was Kenneth Gould, a Great Falls native who grew up near one of the victims.
Patricia Kalitzke, 16, and her boyfriend Lloyd Duane Bogle, 18, were found fatally shot in the head near Bogle's car in 1956, in a case that baffled investigators for decades.
"Two popular kids who were essentially gunned down in a Lover's Lane situation," said Kadner.
A DNA profile of a suspect in 2001 was developed using forensic evidence preserved from Kalitzke's 1956 autopsy, Kadner said. The evidence was compared to DNA available in commercial databases.
"They built a family tree backward and then forward to develop (the link to) Kenneth Gould," Kadner said.
By the time Gould was determined to be the prime suspect, investigators had no way to confirm it directly with DNA. "He died in 2007 and was cremated," Sgt. Kadner said.
Police were able to find two children of Gould's who submitted DNA samples, which matched the evidence collected in 1956. It was later determined that Gould and Kalitzke grew up near each other.
Kadner believes it is the oldest murder case to be solved with this kind of genetic review.
Even though he knew all along that the killer was likely to be dead by the time he was found, Kadner said he felt driven to solve the case after reviewing the decades of files pieced together by past detectives.
"They poured their heart and souls into that case, and it just made you realize how hard investigators had worked," he said. "The same thing happens to you, essentially."
According to the detective, police still do not have a motive in the case, but the victims' families have expressed gratitude to at least have some answers 65 years later.