PORTLAND, Ore. (AP) — A federal agency is offering a $50,000 reward for information about the deaths of three endangered gray wolves from the same pack in southern Oregon.

The collars from two gray wolves sent a mortality signal Dec. 29. State wildlife officials responded and found three dead wolves, two with collars and one without, the U.S. Fish and Wildlife Service said in a statement.

The collared wolves were an adult breeding female and a subadult from the Gearhart Mountain Pack. The other wolf killed was also a subadult.

The Oregon Department of Fish and Wildlife said it is aware of seven wolves remaining in the pack, including a breeding male.

Officials did not indicate in the statement how the wolves died. A phone message left Saturday seeking more information was not immediately returned.

Gray wolves are protected by federal law under the Endangered Species Act. It is illegal to hurt or kill them. The reward is for information leading to an arrest, criminal conviction or fine.

In Oregon, gray wolves are listed as endangered in the western two-thirds of the state.

The three wolves were killed east of Bly in southern Oregon’s Klamath County, or about 310 miles (499 kilometers) southeast of Portland. They were an area that wolves are known to inhabit, stretching across Klamath and Lake counties, just north of the Oregon-California border.