Federal agents have charged three men in the stabbing death of a disabled man on the Warm Springs Reservation. FBI agents accuse Ronald L. McKinley, 23, Angelo Fuentes, 22, and Tony Gilbert Jr., 18, of stabbing 26-year-old Michael Saludo several times and leaving his body at the Lower Dry Creek Campground. The accused murderers also are residents of the reservation. The body was found July 12, the day after the four men drove to the campground in Saludo's car after a party. "We think that the motive for taking him out there was a robbery,'' said James D. Cole, chief detective for the Warm Springs Police Department. A preliminary hearing was scheduled for Monday to determine whether there is probable cause to hold the men pending a grand jury indictment, said James D. Lang, a lawyer representing Fuentes.