RAPID CITY, S.D. ? A federal jury Friday convicted a former American Indian Movement member of murdering a woman who had been suspected of being a government informant.

Arlo Looking Cloud, 50, faces a mandatory life sentence for the 1975 shooting death of Anna Mae Pictou Aquash, a 30-year-old fellow member of the Indian militant group. Her frozen body was found in 1976 on South Dakota’s Pine Ridge Indian Reservation.

Jurors deliberated for about seven hours before convicting Looking Cloud of first-degree murder committed in the perpetration of a kidnapping. He had been indicted in March with another former AIM member, John Graham.

Looking Cloud’s attorney, Tim Rensch, said he would appeal.

Authorities said they only recently found enough evidence to prosecute the case. A break came when the former common-law wife of former AIM leader Dennis Banks came forward.

Graham is free on bail in Canada and plans to fight extradition.

The slaying came amid a series of bloody clashes in the mid-1970s between federal agents and AIM, which agitated for treaty rights and self-determination for Indians. Aquash, a member of Mi’kmaq Tribe of Canada, was among the Indian militants who occupied the village of Wounded Knee for 71 days in 1973.

Prosecutors said Aquash’s hands were tied and she begged for her life as she was led to the edge of a cliff in South Dakota, where she was shot in the back of the head.

Looking Cloud admitted he helped drive Aquash from Denver to Rapid City and eventually to the place where he says Graham shot her, but he insisted he did not know she was going to be killed.

Rensch said in closing arguments Friday that prosecutors had not proven Looking Cloud knowingly took part in the killing.

“They have to prove beyond any reasonable doubt that in his mind he wanted Miss Pictou Aquash to die,” Rensch said. “Tagging along isn’t enough.”

U.S. Atty. Jim McMahon told jurors Looking Cloud had been a willing participant in Aquash’s killing.

“She gets to the edge of the cliff and asks to pray and she’s shot in the back of the head,” McMahon said. “You don’t have to go any further in this case than that there. Because to haul somebody that distance to the edge of the cliff is premeditated, cold-blooded murder.

“There weren’t any surprises. She begged all the way up,” McMahon said.

Rensch criticized prosecutors for testimony about the violence of the American Indian Movement that he said had nothing to do with the case.

“They’ve taken a lightning rod of prejudice … of the American Indian Movement from the early 1970s and … hung it over his head,” Rensch said.

McMahon said the evidence about AIM was intended to lay the background for allegations among its members at the time that Aquash was a government spy.