Complex sentence: Marv and his associates steal the money, but things then go horribly wrong when it's discovered Marv's father has hanged himself, then Vince and two accomplices intervene and shoots one of Marv's unarmed associates, and he is horrified.
Split into simpler sentences: Marv and his associates steal the money, but Vince and two accomplices intervene. Vince shoots one of Marv's unarmed associates, and he is horrified.