Searchers with dogs and on horseback failed to find a missing Casper hunter Tuesday, over a week after he was reported missing in the rugged Bighorn Mountain country of Montana's Crow Indian Reservation.

Relatives said 49-year-old Robert "Bugsy" Springfield went bow hunting in the Bighorns on Sept. 19 with one of his sons and a friend. They reportedly split up with Springfield the next day, and the two of them came out of the mountains that evening.

Veronica Springfield, the wife of the missing man, said between 100 and 150 people were looking Tuesday with the aid of four search dogs from Missoula.

She said early on, tracks were found that might have been left by her husband, but "there have been so many people in and out now, the tracks are kind of walked over."

At this point, she said most of the searchers are people who live on the reservation. Springfield is an enrolled member of the Crow Tribe.

Veronica Springfield said her husband was unemployed in Casper after suffering an injury in an oil field accident.

Big Horn County (Mont.) sheriff's Sgt. Rick Kroger said two deputies and four county road workers took part in the search Thursday and Friday, but pulled out after that. He said the most active agency, at least in the early days of the search, was the federal Bureau of Indian Affairs, which had people from law enforcement, fish and game and forestry taking part.

A spokesman at the Billings office of the BIA referred all questions to a spokeswoman in Washington, D.C., who could not be reached for comment.

Myra Gros Ventre, Springfield's adoptive sister, said a helicopter and an airplane have been aiding the volunteer searchers off and on, but people were needed on the ground because the mountains in the search area are full of steep, dense canyons and caves.

It snowed on the searchers a couple of times last week and it has been cold in the Bighorns, but Springfield was thought to be well equipped and supplied with warm clothes.

"We still have hopes," Gros Ventre said.