According to accounts, a Wyoming man ran the wolf down with a snowmobile in late February, disabling it. He then took it to a local bar and posed for photos before shooting it.
Erik Molvar, executive director of the Western Watersheds Project, said federal protections under the Endangered Species Act are essential because there are still those who don't respect wildlife.
"That's why wolves were driven extinct in the first place, is because these types of people were the ones who controlled the public policy discussion throughout much of the 20th century when wolves were driven extinct," he said.
In early February, the U.S. Fish and Wildlife Service declined to restore protections for gray wolves in western states. The agency said it concluded the animals weren't in danger of extinction under the Endangered Species Act.
The lawsuit was filed by the Western Environmental Law Center on behalf of Western Watersheds and a coalition of nine other conservation groups.
Molvar believes the federal agency's decision not to re-designate western wolves as "endangered" was profoundly misguided. He said some states such as New Mexico and Colorado have adopted extra penalties for killing wolves, but the Endangered Species Act lets hunters in other states off the hook if they claim it was a case of mistaken identity.
"There were special loopholes for Wyoming, Idaho and Montana - and also parts of Oregon, Washington and Utah - so it does beg the question of how often this is happening quietly and under the radar," he explained.
In Wyoming, wolves and coyotes, which are considered predators, aren't eligible for protections under the state's animal cruelty statute. To date, the only penalty inflicted on the person shown on social media tormenting the wolf was a $250 fine by the Wyoming Game and Fish Department.