Officials are looking for leads after two deer were shot and left to rot near a parking lot in the Ringold area of the Hanford Reach National Monument.
A hunter found one of the deer, a doe, Sunday and alerted the Washington State Patrol.
State Department of Fish and Wildlife initially investigated and also found a two-point buck nearby.
The deer appeared to have been shot several days before they were found, said Richie Bare, game warden for U.S. Fish and Wildlife.
The animals were shot with a high-powered rifle, even though the current hunting season allows only shotguns loaded with slugs for deer. In addition, only three-point or higher bucks and no does may be legally shot in the game management unit where the deer carcasses were found, Bare said.
Anyone with information is asked to call the Washington Department of Fish and Wildlife poaching hotline at 877-933-9847. Callers may remain anonymous.