Over thirty years after Michella Welch went missing in a Washington park, investigators have arrested a suspect in her slaying, authorities announced Friday. Gary Charles Hartman, 66, was charged with murder and rape after police found DNA that matched genetic material from the crime scene on his used napkin. In May, Tacoma police enlisted the help of a genetic genealogist who ran a DNA sample from the suspect through a public database, leading investigators to Hartman and his brother. Police surveilled the brothers, and surreptitiously followed Hartman to a restaurant, where they collected his used napkin. Sure enough, the DNA on the napkin was a match to the DNA found at the crime scene. Hartman, who was working as a community nurse specialist at Western State Hospital, does not have any prior convictions. Welch went missing in August 1986 in Puget Park. Her body was later found, and authorities determined she’d been “sexually assaulted and killed by a cut to the neck and blunt force trauma to the head,” The News Tribune reported.