WASHINGTON (AP) — A federal law enforcement official says the FBI is investigating whether the remains of a dead man in the Pacific Northwest are those of D.B. Cooper, who hijacked a passenger jet in 1971 and parachuted from the airliner with $200,000 in ransom.

Cooper hasn't been found.

The official says the FBI got a tip three months ago from a law enforcement source about a possible suspect. The official requested anonymity to discuss an ongoing investigation.

FBI agents requested personal effects of the possible suspect, who died years ago of natural causes. The FBI is trying to find fingerprints or DNA on the effects to compare with items the hijacker left behind.

Copyright 2011 The Associated Press.