BILLINGS, Mont. (AP) - Four descendants of Sioux Chief Sitting Bull want the bones of their famous ancestor moved from what is believed to be his resting place in South Dakota to the Little Bighorn Battlefield in Montana.

Ernie LaPointe, of Lead, S.D., the spokesman for the four family members, said that for 50 years, Sitting Bull's grave on the Standing Rock Sioux Reservation near Mobridge, S.D., has been neglected and dishonored. Now, LaPointe said, new owners of the property plan to exploit the legendary Lakota leader's memory.

LaPointe and his sisters, Marlene Little Spotted Horse Andersen, Ethel Little Spotted Horse Bates and Lydia Little Spotted Horse Red Paint, sent letters Wednesday advising government and tribal officials in North Dakota, South Dakota and Montana of their intent to have the remains moved.

"This is to notify you and other interested parties of family right and authority to re-inter our great-grandfather Sitting Bull to Little Bighorn Battlefield National Monument, Montana," it says. "We do this because North Dakota, South Dakota and the Standing Rock Sioux Tribe have not honored their promise for proper care and maintenance of our grandfather's burial site."

Darrell Cook, superintendent at Little Bighorn Battlefield National Monument, said the battlefield has agreed to help LaPointe and his sisters.

"We recognize Sitting Bull's legacy and that it is at the Little Bighorn," Cook said.

Sitting Bull led an alliance of Sioux, Cheyenne and others in defiance of government orders to settle on reservations. His struggle culminated in the defeat of the 7th Cavalry at Little Bighorn on June 25, 1876.

The National Park Service and Sitting Bull's direct descendants have a long-established working relationship that dates to planning for the new Indian Memorial at the Battlefield, Cook said.

"I think that's why they felt comfortable coming to us about this," he said.

Sitting Bull, who was killed in a battle with Indian police in 1890, was originally buried near Fort Yates, N.D., in the northern part of the Standing Rock Reservation.

Sitting Bull's ancestors moved his remains to South Dakota in the 1950s, although some contend the bones were not his, but those of another man. Part of the site's attraction is the mystery and controversy.

The catalyst for the great-grandchildren's decision apparently was a proposal by the nonprofit Sitting Bull Monument Foundation, which recently purchased the grave site from a private owner. According to its Web site, the foundation's plans include preservation and protection of the grave site and development of an educational and cultural center and museum. It would also include a riverfront recreational development, amphitheater, snack bar, restaurant and gift shop.

LaPointe said he and his sisters were not consulted about the plans and don't want to see a restaurant and gift shops at the grave site.