Complex sentence: When Hastings learns about the brothers' investigations, he frames them for murder of the sheriff (Paul Fix) and, not content with seeing them going to prison, arranges an ambush in which Matt is killed and Bud seriously injured.
Split into simpler sentences: When Hastings learns about the brothers' investigations, he frames them for murder of the sheriff (Paul Fix). Then, not content with seeing them go to prison, Hastings arranges an ambush in which Matt is killed and Bud seriously injured.