SEATTLE (AP) — Washington state wildlife agents are preparing to kill up to four more gray wolves in the northeast corner of the state after investigators said the pack has injured or eaten livestock.

The Seattle Times reports seven environmental groups on Friday urged the director of the state Department of Fish and Wildlife to stop the wolf kill, saying the agency has not proved beyond a doubt that the predators were responsible for the cattle deaths — or that it had exhausted other nonlethal means to keep the wolves and cows apart.

State and federal wildlife officials have been keeping an eye on the wolves, members of the so-called Wedge Pack along the Canadian border, since at least mid-July. That's when ranchers reported a cow and calf had been attacked by a wolf.

The state has already killed one wolf there earlier this month.