RAPID CITY, S.D. – Trial is set to begin in Rapid City, S.D., for the man accused of providing a gun that was used more than 34 years ago to kill an American Indian Movement activist who has become an icon for many of North America's native people.

Richard Marshall has pleaded not guilty to aiding and abetting the December 1975 shooting of fellow AIM activist Annie Mae Aquash, who came to the Pine Ridge Indian Reservation from Canada in the early 1970s to join the movement's efforts.

Prosecutors have said Marshall at some point provided a .32-caliber revolver allegedly used by another former AIM member, John Graham, who is accused of shooting Aquash in the Badlands as she begged for her life.

Graham and fellow activist Arlo Looking Cloud were indicted in the case in 2003. Looking Cloud was convicted in 2004 of being an accomplice to Aquash's murder and sentenced to life in prison. He's expected to be a key witness in Marshall's federal trial.

Graham has pleaded not guilty to kidnapping and murder and could go on trial this summer.

Prosecutors have said that Marshall supplied the revolver when Graham, Looking Cloud and Theda Clarke stopped at Marshall's house near Allen the day Aquash was killed.

Witnesses testified at Looking Cloud's trial that the trio had driven Aquash from Denver to Rapid City and eventually to the Badlands on orders from AIM leaders who ordered her killed because they thought she was a government informant. Federal investigators have denied Aquash was a snitch.

Cleo Gates, Marshall's wife, testified that Aquash stayed with her in the kitchen while the others went into a back bedroom with Marshall. Gates said under questioning by prosecutors that her husband did not keep a gun in the bedroom.

Marshall's lawyer, Dana Hanna, has taken issue with Looking Cloud's previous statements about his knowledge of the killing and has tried in court documents to pick away at the credibility of Looking Cloud and other government witnesses.

Hanna wrote in proposed jury instructions that Looking Cloud is testifying against Marshall in hopes of getting his sentenced reduced.

Jury selection is scheduled to begin Wednesday. A competency hearing is scheduled Tuesday to determine whether Clarke, who is now in her 80s, is capable of testifying during the trial.

Graham, who is from Canada's Yukon territory and belongs to the Southern Tutchone tribe, awaits trial in state court. Federal charges were dropped after federal courts concluded the U.S. did not have jurisdiction because he does not belong to an American Indian tribe.

Aquash was a member of Mi'kmaq Tribe of Nova Scotia and was reburied there in 2004. Looking Cloud, Marshall and Clarke are Lakotas from Pine Ridge.

AIM was formed in the 1960s to combat what some perceived as a lack of interest in Indian issues within the American political system. It first gained national attention in 1972 when it took over the Bureau of Indian Affairs headquarters in Washington. The next year, the group occupied Wounded Knee on the Pine Ridge reservation during a 71-day standoff.

The hostility with the federal government came to a head in 1975 when two FBI agents were shot and killed at Pine Ridge. A federal jury in Fargo, N.D., convicted Leonard Peltier of the killings and sentenced him to life in prison. Peltier, who grew up on the Turtle Mountain Reservation in North Dakota, has maintained his innocence.

During Looking Cloud's trial, Darlene Nichols-Ecoffey – an Aquash friend and former husband of AIM leader Dennis Banks – testified she heard Peltier say he thought Aquash was a snitch. Nichols-Ecoffey also told jurors she was with Aquash when Peltier bragged about killing the two FBI agents.

Barry Bachrach, Peltier's lawyer, denied the accusation and said the prosecution's purpose was to smear AIM and cover up history.