A home invasion in Barrie has detectives going door-to-door. Around 4:00 this morning, three men allegedly forced their way into a Lillian Crescent home and assaulted one of the four residents. About 90 minutes later, police say the trio fled, leaving a 55-year-old man in need of serious medical attention. The other three were not hurt. Officers will be canvassing the area this evening, in the hopes of finding a lead. Investigators believe this to be a targeted attack, and feel there is no threat to public safety.