On this day, Feb. 24, in 1976, the body of American Indian Movement, or AIM, activist Anna Mae Pictou Aquash was found during an unseasonably warm February on the Pine Ridge Indian Reservation in South Dakota.

AIM, founded in the late 1960s to protest the U.S. government's treatment of Indians, had been under constant investigation by the FBI.

AIM members suspected Aquash of being a government spy.

Investigators said she had been tied up, raped and marched to the top of a cliff. She was shot in the head, and her body tumbled to the bottom of the ravine.

Federal agents investigated for years but didn't bring indictments until 2003.

Arlo Looking Cloud was convicted in 2004, John Graham in 2010, and both received life sentences.

- Scott McCabe