Seattle, WA -

Federal wildlife agents are investigating the death of an endangered gray wolf in Okanogan County.

U.S. Fish and Wildlife spokesman Doug Zimmer says the adult female wolf was shot and killed on Sept. 20 during a big game hunt in the area. He says hunters were in the field hunting elk or deer in the Pasayten Wilderness, and reported to state wildlife officials that they had shot and killed a wolf.

Zimmer says federal wildlife officers are working to determine whether the shooting was a legitimate accident, or killed under other circumstances.

It's not legal to hunt wolves in Washington state. Gray wolves are federally listed as endangered in the western two-thirds of Washington.

He says the gray wolf is an un-collared female but it's unclear which pack she belonged to.