33-year-old Sudanese refugee Dau Mabil, who escaped civil war, was found dead in a river; brother Bul Mabil calls for federal investigation, dissatisfied with authorities' handling and autopsy results.

33-year-old Dau Mabil, who escaped Sudan's civil war as a child and built a life in Mississippi, was found dead in a river, sparking calls for a federal investigation into his mysterious death. Mabil disappeared on March 25 while going for a walk near the Mississippi Civil Rights Museum. His brother, Bul Mabil, has expressed dissatisfaction with the way authorities have handled the case, questioning initial autopsy results.