DePetro.com has learned Woonsocket killer Sean Rivera was arrested in the past for arson, and sentenced to home confinement with an ankle bracelet. Sources tell us Rivera was arrested for trying to burn down the house of the new boyfriend of an ex-girlfriend who broke up with him. Sources tell us Rivera was so upset over a girlfriend dating a new guy that he set fire to the new boyfriend’s porch and back of his house. Sean Rivera did not take news of the breakup well. DEPETRO.COM has also learned the gun used Monday night in Woonsocket was most likely from a friend he had in New Hampshire. The daughter of the mother killed told DEPETRO.COM Rivera suddenly snapped when she told him the relationship was over. Rivera proceeded to shoot and kill her mom and stepdad. The daughter told us when she first met Rivera he had an ankle bracelet, but she never asked what he had done.