The butchered remains of a dolphin were found on a New Jersey beach, and federal authorities are investigating.The Marine Mammal Stranding Center, which responds to reports of dead or distressed marine animals that come ashore in New Jersey, said the remains of a common dolphin were found Wednesday on the beach in Allenhurst, just north of Asbury Park.The dolphin appeared to have been butchered," the center said in a statement.The animals flesh had been completely removed with clean cuts from a sharp instrument, leaving only the head, dorsal fin and flukes, the center wrote. The animals organs, except for the heart and lungs, had been removed.RELATED STORY | More than 100 dead dolphins found in Amazon amid historic droughtWitnesses had reported seeing a dolphin of the same species struggling in the surf Tuesday night a block from where the remains were found the next day.But the animal was able to swim over a sand bar and back out to sea. It was not known whether it was the same animal whose remains were found the next day.The common dolphin is not listed as threatened or endangered. The case is being investigated by the National Oceanic and Atmospheric Administration's Office of Law Enforcement.