Sitting Bull's four surviving great-grandchildren want the bones of their famous ancestor moved from a cement-clad grave in South Dakota to Little Bighorn Battlefield in Montana.

Ernie LaPointe of Lead, S.D., the spokesman for the family, 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 says, new owners of the property plan to exploit the legendary Lakota political and spiritual 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 the Dakotas 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 a resounding 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.

Before a final decision is reached on placing the remains at the battlefield, Cook said, the National Park Service will probably order an environmental assessment, so the public will have a chance to comment.

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.

The foundation has already completed a major cleanup at the grave site and has installed electricity and lighting.

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.

Reached by telephone Wednesday morning, Bryan Defender, a member of the Standing Rock Tribe and one of the founders of the Sitting Bull Monument Foundation, said commercialization was never his intent.

"Our motivation behind this is very sincere,'' he said. "The development is a very positive thing. The only thing I want to do is display our culture, our history in an authentic, positive way and to pay tribute to a leader who has never been properly paid tribute."

He agreed that until 2005, when he and Rhett Albers bought the land where Sitting Bull rests, the grave had been neglected. But the foundation has cleaned it up and is raising money for a $12 million complex to honor Sitting Bull and the Lakota heritage, Defender said.

"I'd like to call him (LaPointe) and talk to him about this," he said. "I would absolutely have to take a look at it."

LaDonna Brave Bull Allard, tourism director for Standing Rock, said Wednesday that she had not heard about LaPointe's letter. Her first reaction to hearing of his plan: "I don't think that's possible."

She said that although LaPointe has rights, he is not enrolled at Standing Rock and she doesn't know what rights he has on reservation lands. That would be a matter for the tribal chairman to comment, Allard said. He was spending the day with Sen. Byron Dorgan, D.-N.D., and was unavailable Wednesday, she said.