RAPID CITY, S.D. (AP) – A man serving a life sentence for his role in the 1975 slaying of an American Indian Movement activist testified Thursday that he witnessed another man supply the gun used in the killing.

Arlo Looking Cloud testified Thursday in the federal trial for Richard Marshall, who has pleaded not guilty to aiding and abetting in the death of AIM activist Annie Mae Aquash. Looking Cloud said Marshall gave a .32-caliber revolver and a box of shells to one of the AIM members with Looking Cloud the night Aquash was killed at a South Dakota Indian reservation.

Looking Cloud was convicted of murder in 2004 for his role in Aquash's death and was sentenced to life in prison. Marshall's lawyer, Dana Hanna, says Looking Cloud's testimony is not credible.

Prosecutors claim AIM leaders ordered Aquash killed because they thought she was a government informant – something federal investigators have denied. Prosecutors say she was taken from Denver, where she was hiding from an illegal weapons charge, and driven to South Dakota.

After many unsuccessful attempts to get the case to court, Looking Cloud and the alleged gunman, John Graham, were indicted in 2003.

Looking Cloud testified that he saw Marshall pull a box out of a night stand in the bedroom of his house. “He opens the box, and there's a pistol in it,” Looking Cloud testified.

Looking Cloud said Marshall gave the gun to Theda Clarke, who eventually gave it to Graham. Hours later, Graham shot Aquash in the back of the head in the Badlands of the Pine Ridge Indian Reservation, Looking Cloud told the jury.

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.

Hanna questioned Looking Cloud about conflicting statements he gave to law enforcement and witnesses about the Aquash case, including whether he and the other AIM members stopped at Marshall's house the night of the slaying and whether Marshall gave Clarke the gun. Hanna said Looking Cloud owned the gun and handed it to Graham at the crime scene, which Looking Cloud denied.

Hanna said Looking Cloud recently changed his story in hopes of getting his prison sentence reduced. Looking Cloud was convicted in 2004 and will eligible for parole in 2014.

Hanna also noted that Looking Cloud has a record that includes 41 criminal cases in Colorado alone.

Hanna questioned Looking Cloud about a witness at his trial, Richard Two Elk, who testified that Looking Cloud told him the weapon was his.

“I never said nothing like that to Richard Two Elk,” Looking Cloud said.

Hanna is scheduled to resume questioning of Looking Cloud on Friday.

The first full day of trial began with testimony from some of the last people to see Aquash alive. Troy Lynn Yellow Wood, a woman who owned a house in Denver where Aquash stayed before she was abducted to South Dakota, said Aquash was led out of her house with her head bowed, like a prisoner. That came after a meeting with AIM members and others about whether Aquash was an informant.

“I think she believed her life was coming to an end,” Yellow Wood said.

Others, including Looking Cloud, testified they didn't think Aquash would be killed. Looking Cloud said he thought AIM members just wanted to scare her.

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.

“When AIM came along, they brought this pride to our people,” Yellow Wood said. “You wanted to be a part of it. You wanted to be recognized and identified as who you were and who your family was. It was an awakening.”

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.