The investigation involves the FBI, the Justice Department's Civil Rights Division and the United States Attorney's office. The Mississippi Bureau of Investigation is also involved.
The man was last seen March 2 and was reported missing by his family days later, FBI Supervisory Special Agent Jason Pack said in a statement. Pack says the cause of death has not been determined, and authorities aren't sure if it's a homicide or a suicide.
Walker said that about 25 minutes after the officers started the search, they found the body hanging in the woods about 200 yards (180 meters) from Byrd's house.
None of the authorities has positively identified the body that was found as Byrd's, however. Claiborne County Sheriff Marvin Lucas Sr. Said a positive identification will not be available until the completion of an autopsy, which he said also should help determine whether the death was a homicide or a suicide. Lucas said the body has been sent to the state Crime Lab. He said the body was found hanging by a bedsheet.