Chilling details emerged Monday about the violent tendencies of Robert Card, the Maine gunman who killed 18 people last week, with CNN reporting he’d often answer his door with a pistol in hand and that a colleague feared he was “going to snap” at any time. Those details were included in a report related to a failed wellness check in September during which Card repeatedly refused to answer the door to cops. Card’s relatives told The Daily Beast that he’d been “hearing voices” after he got powerful hearing aids in recent months. Citing a source who viewed documents from the Maine National Guard, CNN reported that Card shoved a fellow guardsmen in a parking lot in July, reportedly claiming that he’d heard the man calling him a pedophile. The guardsmen flagged the incident and Card spent two weeks at a psychiatric facility. Another troubling incident occurred after his release, however, with a guardsman telling authorities that Card punched him after he told Card to stop talking about shooting up a National Guard base.