GRAND FORKS - Two men in custody on unrelated charges are "persons of interest" in the death this week of a man at the Spirit Lake Indian Reservation, officials said Friday.

Kyle Loven, an FBI spokesman in Minneapolis, identified the dead man as Dustin Jackson. TV news reports citing information from family members said he was 38 and that his badly beaten body had been found by a passer-by in a reservation ditch.

Loven said one of the persons of interest, Clifford Monteith, is in tribal custody.

Tim Purdon, U.S. attorney for North Dakota, said Elmer Flying Horse is being held on a federal warrant, also on an unrelated charge.

The officials said they could provide no further details Friday, but Loven said the investigation remains active.