The Osage Indian murders were a series of murders of Osage people in Osage County, Oklahoma in the early 1920s; newspapers described the increasing number of unsolved murders as the "Reign of Terror". Estimates are that 60 or more wealthy, full-blood Osage native Americans were killed from 1921 to 1925. The murders appear to have been committed by people intent on taking over the great wealth of the Osage, whose land was producing valuable oil, and who each had headrights that earned lucrative annual royalties. Investigation by law enforcement, including the predecessor to the FBI, also revealed extensive corruption among local officials involved in the Osage guardian program. Most of the murders were never prosecuted, but some men were convicted and sentenced.