An amateur sleuth is suing the FBI for access to evidence from a famous cold case.

Eric Ulis is looking into the vanishing of the legendary plane hijacker D.B. Cooper.Cooper is said to have held a plane for ransom in 1971, collecting $200,000 before going back up in the air, skydiving out of the plane with cash in hand and disappearing.

Ulis wants to collect a DNA sample from a tie clip left behind by Cooper, believing that the FBI didn't test the metal clasp of the tie.

A former FBI agent says he doesn't think the clasp was removed for testing, however, any DNA has likely been compromised due to old methods of collecting evidence.