Federal authorities say they are investigating the possibility that a person deliberately attacked an endangered loggerhead sea turtle that died after being found injured at a North Carolina national park.

The Costal Conservation Association said in a statement Friday that the turtle was found with a gaping hole in its head by a park ranger at the Cape Lookout National Seashore in late July. The group says North Carolina State University veterinarians treated the 70-pound turtle for three days, then it was euthanized July 29.

The statement says researchers determined after the turtle's death that a person caused the blunt force trauma to its head.

Allyson Rogers of the National Oceanic and Atmospheric Administration confirms that authorities are investigating the circumstances of the turtle's death.

The coastal association says a $7,500 reward is offered for information leading to an arrest of anyone connected with the attack.