The FBI says federal authorities are investigating the hanging death of a black man in Mississippi.

The investigation is being done by the FBI, the Justice Department's Civil Rights Division and the United States Attorney's office.

FBI spokesman Jason Pack said Thursday that the man had not been seen since March 2 and was found dead in the woods near Port Gibson during a search by local law enforcement.

Pack says the cause and manner of death has not been determined, and authorities aren't sure if it's a homicide or a suicide. He says investigators are "trying to get the facts and determine all that right now."