The neighborhood watchman who in February shot 17-year-old Trayvon Martin was once fired from his job as a security guard for "being too aggressive," according to a new report.

An unnamed former co-worker told the New York Daily News that George Zimmerman was paid under-the-table for providing security for illegal house parties between 2001 and 2005, but was let go because his anger issues "became a liability."

"Usually he was just a cool guy," the former co-worker explained. "He liked to drink and hang with the women like the rest of us. ... But it was like Jekyll and Hyde. When the dude snapped, he snapped."

“He had a temper and he became a liability,” he recalled. “One time this woman was acting a little out of control. She was drunk. George lost his cool and totally overreacted. ... It was weird, because he was such a cool guy, but he got all nuts. He picked her up and threw her. It was pure rage. She twisted her ankle. Everyone was flipping out.”

In 2005, the same year that Zimmerman lost his security guard job, he was also arrested for "resisting officer with violence" and "battery of law enforcement officer," both third-degree felonies. Those charges were dropped after he agreed to enter an alcohol education program.

MSNBC reported that his ex-fiancee, Veronica Zuazo, alleged domestic violence and filed a motion for a restraining order in 2005. Zimmerman then filed for a restraining order against Zuazo and both later dropped their motions.

Even with all this history, the former co-worker said he was shocked to hear the news that Zimmerman killed Martin.

“He definitely loved being in charge," he said. "He loved the power. Still, I could never see him killing someone. Never."