State and federal wildlife officials are investigating an accidental killing of a Canada lynx by a trapper in far northern Maine.

The discovery of the dead lynx could have implications for a federal court case seeking additional restrictions on trapping in order to protect populations of the threatened wildcats. The plaintiffs in the case already are citing the killed lynx as evidence in their push to curtail trapping throughout northern Maine.

“This incident demonstrates that the current trapping regulations are inadequate to protect lynx and other imperiled species,” said Camilla Fox, a wildlife consultant with the Animal Welfare Institute.

Details of the trapped lynx are still sketchy. The state Department of Inland Fisheries and Wildlife declined comment on the case Wednesday because it is still under investigation.

But in a letter to U.S. District Judge John Woodcock, DIF&W’s attorney said the lynx was found on Nov. 17 by a trapper operating in the wildlife management district that stretches from Fort Kent to Ashland and west to the Allagash River.

The trapper, who reported the incident to the state, had apparently last tended his trap on Nov. 12, as allowed under Maine’s rules for traps intended to quickly kill the animal. The lynx was apparently caught in a trap commonly known as a Conibear, “body-gripper” or “killer-type” trap.

Officials with DIF&W and the U.S. Fish and Wildlife Service are investigating whether the trap was legally set. Jennifer Vashon, a DIF&W biologist, said the she hopes the investigation will be complete by Friday.

Under rules enacted last year in response to an earlier lawsuit over lynx trappings, all body-gripper traps in Wildlife Management Districts 1 through 11 that have a jaw spread of larger than 5 inches must either be set entirely underwater or a minimum of 4 feet above the ground.

DIF&W also requires that all larger body-gripper traps placed above ground must be set on poles or trees no wider than 4 inches in diameter and leaning at an angle of at least 45 degrees.

State officials enacted the rules in an attempt to avoid lynx trappings without prohibiting capture of other smaller game popular with trappers, such as fisher or mink. But members of the Wildlife Alliance of Maine and the Animal Welfare Institute point out in their current lawsuit that eight lynx were still inadvertently trapped last year after the new rules were put in place.

All eight of the wildcats were found alive and released. But members of the two groups charge that DIF&W is violating the federal Endangered Species Act by permitting trapping activities that harass, harm or potentially kill the protected cats.

“The point we are emphasizing is not about the trappers being at fault, per se,” said Fox, who credited the trapper for reporting the lynx. “But the state must promulgate regulations that protect species listed under the Endangered Species Act.”

During a court hearing last week, Woodcock pressed the attorney for the two groups for evidence that Maine’s lynx are being harmed when all of the cats trapped last year were apparently released with little to no visible injury.

“All I’ve got is eight lynx that get caught in foothold traps and walk away ultimately, one a little gimpy,” Woodcock said. “Where is the irreparable harm?”

Fox said she believes this week’s discovery underscores the plaintiffs’ push for Woodcock to suspend some types of trapping in northern Maine until the state receives a federal permit that allows a limited “take” of protected species.

A representative for the Maine Trappers Association could not be reached for comment Wednesday afternoon.

Lynx are medium-size cats with large, fur-covered paws that allow them to pursue their primary food source: the snowshoe hare, in deep snow. They are listed as a threatened species under the Endangered Species Act.

Biologists estimate that there are approximately 500 lynx in Maine, which is the only state in the eastern U.S. with a self-sustaining population of the cats.