Jurors in Washington state on Friday heard about the mysterious final days of a young Canadian couple killed in 1987—as well as the novel method authorities used to finally make an arrest three decades later, the AP reports. William Earl Talbott II was arrested last year and charged with aggravated murder, after authorities said they used genetic genealogy to identify him as the person who left his DNA on the clothing of one of the victims. The practice involves identifying suspects by entering crime-scene DNA profiles into public databases that people have used for years to fill out their family trees. Opening statements began with a prosecutor describing how 18-year-old Tanya Van Cuylenborg and her boyfriend, 20-year-old Jay Cook, left British Columbia for what was supposed to be an overnight trip to Seattle in November 1987.
When they didn't return, their families began a frantic search for them, including renting a plane to try to spot the copper-colored Ford van they had been driving. About a week later, Van Cuylenborg's body was found down an embankment in rural Skagit County, north of Seattle. She had been shot in the back of the head. Hunters found Cook dead two days later, beaten and strangled, in brush near a bridge over the Snoqualmie River in Monroe—about 60 miles from where his girlfriend was discovered. Detectives investigated hundreds of leads for decades, then used a DNA lab and concluded that the killer was a male child of William and Patricia Talbott. William Talbott II, now 56, was their only son. He was 24 at the time of the killings and lived near where Cook's body was found. (DNA evidence has also led to an arrest in the 1987 killing of a soldier.)