Man breaks into 90 yo house, and 90 minutes later the man has a heart attack. Man brings baseball bat into shop, man has heart attack immediately. It must be proved that but for d"s act or omission, the event would not have occurred. Omission when there is a duty of care, or a duty to uncause what he has started. But for principle is only a starting point. The prosecution needs only to establish that it was a cause outside the de minimis range. Intervening acts or events can "break the chain" of causation. D assaults v, leaving him unconscious in his home. Chain of causation broken because d could not foresee that. D assaults v, leaving him on a deserted beach when tide is out. Chain of causation not broken because d should"ve foreseen that. Training your dog to steal-dog is innocent agent.