Complex sentence: In these surprise raids into the United States the Apaches moved quickly to attack isolated ranches, wagon trains, prospectors, and travelers and they often killed all persons they encountered to defer detection and pursuit as long as possible.
Split into simpler sentences: In these surprise raids into the United States the Apaches moved quickly to attack isolated ranches, wagon trains, prospectors, and travelers. During these raids the Apaches often killed all the persons they encountered to defer detection and pursuit as long as possible.