The trail grew cold until 2005. Shortly before she died, Asher's mother asked relatives to get in touch with her son.
"She asked various family members to assist her in using the 'secret' number to call 'Billy,'" the FBI said. Agents had been tipped off about the conversation by a source.
Armed with that information, agents scoured phone records of people who they believed may have helped fulfill the mother's request.
They found two phone calls made to a home in Salida, California, to a man named Garry Donald Webb. The calls had been made two days before the mother died.
Agents looked at Webb's driver's license photo. It resembled an older, thinner Asher.
Authorities placed the home under surveillance. They also kept a watch on a trucking business where he was said to work.
On Friday, agents saw Asher leaving the home and confronted him.
More here: Mother's request leads FBI to fugitive on run for 36 years -