A discarded restaurant napkin helped police officials in the US to identify a murder suspect 32 years after he committed the crime, a media report said on Friday.Pierce County prosecutors charged Gary Charles Hartman, 66, with first-degree murder and first-degree rape in the 1986 death of a 12-year-old girl.Police say Michella Welch and her two younger sisters went to Puget Park, Tacoma (Washington) on March 26, 1986. About 11 am Michella rode a bicycle home to get lunch. While she was gone, the sisters went to a business to use the restroom.When they returned, they didn’t see Michella and continued to play in a gulch until they noticed the bicycle and lunch at the spot where they were supposed to meet for a picnic, the chief said. The girls notified their baby sitter, who contacted the girls’ mother. Police were called and a search began, CNN reported.A search dog found Michella’s body that night in an isolated area in the gulch, more than a quarter mile away from the play area.“Michella had been sexually assaulted and murdered.” Tacoma Police Chief Don Ramsdell said at a news conference.Police collected evidence but did not make any arrests. Police developed a male DNA profile from crime scene evidence, but found no match in state and national databases. In 2016, police began working with a genetic genealogist.“Genetic genealogy uses a DNA technology to identify subjects by matching the unknown profile to a family member,” Ramsdell said. “Traditional genealogy is then used to build a family tree from publicly available websites.”Two brothers were identified as possible suspects and surveillance began, Ramsdell said. That included Detective Steve Reopelle following Hartman into a restaurant when he met a co-worker for coffee, Ramsdell said.“I observed him using the napkin multiple times,” Reopelle said. “He crumpled it up, put it into a bag and then crumpled that bag up and voluntarily abandoned that bag as he left the restaurant.” The napkin was collected and sent to the Washington State Patrol Crime Laboratory. On Tuesday, the lab told police the DNA on the napkin matched DNA found at the crime scene, Ramsdell said. On Wednesday, police made a traffic stop and took Hartman into custody.