Reno, Nev. ? Military investigators have determined that a helicopter crash that killed five Army National Guardsmen in Afghanistan last month was the result of hostile fire, not an accident.

Militants claimed they shot down the aircraft, but Army investigators initially believed the crash was the result of a mechanical failure or other problem.

“After talking to other people in the area and looking at the wreckage, the conclusion was that it was hostile fire,” Nevada Army National Guard spokeswoman Capt. April Conway said Saturday.

A final report is not expected for more than a month. Investigators will examine the bullet hole that brought the helicopter down, spray patterns of fuel on the ground and how far pieces were strewn, Conway said.