BASIN - No charges will be filed in the shooting death of a Montana man at a campground last weekend after an investigation determined the shooting was likely "justifiable," according to the Big Horn County Sheriff's Department.

Larry P. Thomas, 44, of Roundup, Mont., was found dead Sunday afternoon from a single gunshot wound near the Five Springs Campground, Sheriff Dave Mattis said.

"All the information we have now" indicates Thomas was shot while he was assaulting a man, Mattis said. That man and another man were detained in the Big Horn County Jail while police investigated.

"We're not saying that the homicide was entirely justifiable, but we're saying no charges will be filed," Mattis said.

The sheriff declined to identify those two men, but he said one was from Wyoming and the other was from outside the Rocky Mountain region.

The investigation determined that Thomas and the two other men drove to a campsite at Five Springs in separate vehicles late Saturday night. Thomas was a longtime acquaintance of one of the men, Mattis said.

"The victim had asked his friend to show him where it (the campground) was - to take him up there - with the intent of spending some time there," the sheriff said.

When the two men left in their vehicle, Thomas rammed them from behind with his pickup "for some unknown reason" and off the roadway, according to a sheriff's office news release. Thomas then attacked the driver of the first vehicle and began slamming his head against rocks.

The passenger of the first vehicle grabbed his rifle, warned Thomas to stop and shot him after he continued to beat the other man's head into the rocks, according to the sheriff's office.

Mattis said the two men reported the incident to the police dispatch center in Lovell on Sunday afternoon, shortly after Thomas's body had been found.

The two men were released Wednesday afternoon.

"After sitting down and discussing what happened, we decided charges were not warranted," said Big Horn County Attorney Michelle McColloch Burns. "It was a joint decision between me, the sheriff's office, the Division of Criminal Investigation and the Wyoming Highway Patrol."

"The investigation is completed," Mattis said. "We have a lot of reports to finish writing, but unless additional information is found, the case is concluded."