PIERRE, S.D. (AP) – A woman has pleaded guilty to her role in the killing of American Indian Movement activist Annie Mae Aquash on South Dakota's Pine Ridge reservation 35 years ago. The alleged gunman is scheduled for trial later this month.

Thelma Rios, 65, was charged in state court with one count each of felony murder in relation to kidnapping, and premeditated murder. She pleaded guilty Monday to one count of accessory to kidnapping and was sentenced to five years in prison, which was suspended by Judge John Delaney.

Rios admitted in court to relaying a message to fellow AIM members to have Aquash brought from Denver to Rapid City in December 1975, because they thought she was a government informant. Investigators deny she was a snitch. Rios also said she opened up her apartment so Rios could be interrogated.

“An individual has accepted certain responsibility with respect to the Aquash matter,” said Marty Jackley, South Dakota's attorney general. “I think it was a fair resolution in reference to that acceptance of responsibility.”

Rios was scheduled for trial later this month along with John Graham, who's accused of raping Aquash at Rios' apartment in Rapid City and later killing her near Wanblee. The plea agreement for Rios states she will make herself available to testify at Graham's trial if called by prosecutors.

Rios told Delaney Monday that she heard discussions among other AIM members that Aquash should be killed.

Delaney had earlier ruled that an alleged threat against Aquash by AIM leader Leonard Peltier could be introduced as evidence in the trial. Peltier, who grew up on the Turtle Mountain reservation in North Dakota, is serving two life sentences for killing two FBI agents in a June standoff. The trial was held in Fargo, N.D.

Graham has pleaded not guilty to one count of felony murder in relation to kidnapping, one count of felony murder in relation to rape and one count of premeditated murder. His trial is scheduled to begin Nov. 29 in Rapid City.