BANGOR (AP) – The U.S. Fish and Wildlife Service is investigating northern Maine’s second Canada lynx trapping death in less than a month.

The dead animal was discovered by game wardens Dec. 4 in woods off a road in Stacyville in Aroostook County. Documents filed in federal court say human footprints apparently led from the lynx to a tree that had held a trap.

Because the lynx is listed as a threatened species, two animal welfare groups have sued Maine’s fish and game department for allegedly violating the Endangered Species Act by allowing trapping practices that could ensnare lynx.

The trapper blamed for a Nov. 17 lynx death was not charged because he apparently misinterpreted state rules meant to avoid accidental lynx trappings and immediately reported the incident.

No charges have been filed in the latest death.