By Lori Grannis
MISSOULA, Mont (Reuters) - An elderly woman, her granddaughter and the girl's boyfriend were shot dead on the Crow Indian Reservation in Montana on Tuesday, and authorities searched into the night for the suspected gunman, FBI and tribal officials said.
The suspect, Sheldon Bernard Chase, 22, was "considered armed and extremely dangerous," and was "believed to be responsible" for the three deaths on Tuesday afternoon, the FBI said in a brief statement.
The shootings occurred near Lodge Grass, a rural community of roughly 500 people about 60 miles southeast of Montana's largest city, Billings, and 20 miles north of the Wyoming border.
The Little Bighorn Battlefield National Monument, where Lieutenant Colonel George Armstrong Custer and his cavalry unit died fighting Indian forces in 1876, lies several miles to the north of Lodge Grass on the reservation.
Few details about Tuesday's shooting or those involved were immediately available.
Crow Tribal Chairman Black Eagle told Reuters in a telephone interview that all three victims were tribal members but that the suspect was not.
"I don't know him. He is not a tribal member, but his mother is a tribal member. His father is from North Dakota. That's all I know," the chairman said.
He described the dead as an elderly woman, her granddaughter and the girl's boyfriend.
The chairman said he did not know the circumstances of the shooting, which occurred at a house on a remote corner of the sprawling reservation about 10 miles southwest of Lodge Grass.
"We are doing as well as we can trying to comprehend what happened today," Black Eagle said. "We have been deeply affected and have asked Indian Health Services to provide grief counseling for this tragedy."
He said relatives and friends flocked to the scene of the shooting in its aftermath in support of the victims' families.
The FBI described Chase as standing over 6 feet tall and weighing 230 pounds. They said he may be driving a Toyota with North or South Dakota license plates or a Volkswagen Jetta with expired Montana plates.
(Additional reporting by Ruffin Prevost from Cody, Wyo.; Writing by Steve Gorman; Editing by Cynthia Johnston)