A conservation group is teaming up with the U.S. Fish and Wildlife Service to offer a $20,000 reward for help catching the person or people responsible for the deaths of three gray wolves in Washington state.

They’ve also doubled the reward for information about a killing in Oregon, about 90 minutes south of the Tri-Cities.

The three wolves were killed in a part of the state where wolves are federally protected under the Endangered Species Act. The Center for Biological Diversity also offered a $10,000 reward in each case in addition to the reward provided by U.S. Fish and Wildlife.

Federal wildlife officials announced Thursday they are seeking information related to what they called the illegal killing of a gray wolf reintroduced to Colorado as part of the state’s voter-mandated restoration program.