Police in Sioux City were looking for a man they say was involved in the slaying of Adrian Rojas Hernandez, 20, of Sioux City.
Martin Castellanos, 20, was being sought Monday.
Another man, Ricardo Jaime Vital, 22, has been charged with being an accessory.
Authorities discovered Hernandez's body in a rural area south of Sioux Falls, S.D. They said he died of a single gunshot wound to the head.
Investigators said Hernandez was killed in Sioux City and his body set on fire.