It started back in 1979 in Lenado, a small town near Aspen. Two hikers looking for mushrooms found a body with two bullet wounds.
"We have had real difficulty identifying the person," Pitkin County Sheriff Joe DiSalvo said. He's one of many detectives to look at the case.
The body was partially decomposed when the investigation started.
After nearly three decades investigators identified the body as Donald Allison. They used a missing person's website called NameUs.com and old finger prints from the 70s.
The findings brought closure to his family and daughters who had long thought their father ran away.
"They can now put him to rest the way they want to," DiSalvo said.
Sheriff DiSalvo says the next step is to look for his killer.
"Now we can get to work on trying to figure out how he died," DiSalvo said.
(KUSA-TV © 2012 Multimedia Holdings Corporation)