BILLINGS, Mont. — Three Montana Army National Guard members face trespassing charges after authorities said they landed a Black Hawk helicopter in a mountain pasture on a private ranch to take several elk antlers before flying away.

A witness saw the May 4 landing and the person who owns the property reported it to officials, who tracked down the three guard members, Sweet Grass County Sheriff Alan Ronneberg said Thursday.

The guardsmen had been on a training flight from the city of Billings to Helena, the state capital, said Major Ryan Finnegan with the Montana National Guard. The helicopter landed briefly in the pasture located in the foothills of the Crazy Mountains, where the crew members picked up two individual antlers and an old elk skull with antlers still attached, the sheriff said.

Elk antlers — which grow and drop off male animals annually — are highly prized and can be sold by the pound. They also are collected from the wild as keepsakes.

The antlers and skull taken by the guardsmen were worth a combined $300 to $400, according to Ronneberg. They were later turned over to a state game warden.

Trespassers taking antlers from private land is not uncommon in Montana and other western states.

“This an odd one,” Ronneberg said. “Usually somebody parks on the side of the road and crosses into private ground and picks up a shed,” he said, referring to an antler that’s been shed by an elk.

Citations issued to two of the guardsmen said they “entered posted private property that was posted as trespassing for the purpose of elk antler removal.” The citation for the third again mentioned trespassing and also that “subject landed military helicopter on private property.”

The Sweet Grass County Attorney and Sheriff’s Office are considering additional charges related to the taking of the antlers themselves, but no decision has been made, Ronneberg said. He said those discussions center on whether the antlers were the property of the landowners.

Reached on Thursday by telephone, one of the three guardsmen, Michael Vincent Bray of East Helena, Montana, referred questions to his attorney, who did not immediately respond to a message seeking comment. The other two guardsmen — Perry Wray Woodland of Great Falls and Deni Lynn Draper of Clancy — could not be reached.

They face charges of criminal misdemeanor trespass, which comes with a $185 fine, and do not have to appear in court, said Greg Lemon with Montana Fish, Wildlife and Parks.

Taking antlers from state-owned land is legal in Montana for people with an $8 state conservation license, Lemon said.

Montana National Guard Adjutant General J. Peter Hronek said in a statement he was aware of the case and it was being investigated.

“Appropriate adverse and/or administrative action will take place if the allegations are determined to be true,” Hronek said. “Misuse of military equipment erodes the trust we strive to uphold with the people of Montana.”

Finnegan said a Montana National Guard representative reached out to the owner of the ranch “to provide an update and coordinate for an in person return of the items.”