Native American activist Leonard Peltier faced a parole board in Pennsylvania on Tuesday after spending 33 years in prison for the murder of two FBI agents.

The agents were killed in 1975 during a shootout with members of the American Indian Movement, or AIM, on the Pine Ridge Reservation in South Dakota.

Peltier, a member of the movement, was implicated in the agents' deaths but fled to Canada. He was eventually arrested by the RCMP in Alberta and extradited back to the United States, where he was found guilty of the murders in 1977 and sentenced to two consecutive life sentences in prison.

He maintains his innocence to this day.

Tuesday was his first parole hearing in 15 years. His lawyer, Eric Seitz, said after the hearing that he expects a decision from the U.S. Parole Commission within three weeks.

John Trimbach, the son of an FBI agent who was at Pine Ridge, says Peltier should not be freed until he admits responsibility for what happened and shows remorse.

Peltier's role in the FBI agents' deaths has also been linked to the murder of fellow AIM activist Anna Mae Pictou Aquash, who was from Nova Scotia. A 2003 editorial published in the U.S. native-affairs newspaper News from Indian Country suggested Aquash was killed because she had knowledge of Peltier's involvement in the 1975 shootout.

Peltier's supporters consider him a political prisoner. Over the years they have raised doubts over his guilt and the fairness of his trial, citing coercion of witnesses and falsified affidavits.

From prison, Peltier has remained vocal in the campaign for Native American rights and has earned international accolades for his activism.

This will be the first complete parole hearing for Peltier since 1993. He is applying for full parole.

With files from the Associated Press