Jeremy Goulet, the man suspected of killing two Santa Cruz Police Department officers on Tuesday, had a history of using guns and was considered unstable by some who knew him.

Goulet, 35, was fired on Saturday from his job as a barista at Kind Grind coffee shop amid sexual harassment allegations from a co-worker, and is believed to have shot Sgt. Loran “Butch” Baker and Det. Elizabeth Butler – the first two Santa Cruz Police Department officers to have been killed in the line of duty.

Santa Cruz Police Chief Kevin Vogel called the shooting of Baker and Butler “the darkest day” in the history of the department. A manager at the coffee shop declined to comment to the media.

Goulet was killed in a shootout with police following the incident in Santa Cruz, a city of about 60,000 located about 70 miles south of San Francisco.

In 2008, a Jeremy Peter Goulet, who was then living in Portland, was convicted of a sex crime and allegedly fired off a gun when the boyfriend of a woman he secretly taped showering with his cellphone confronted him, multiple media accounts said. He was convicted of not having a permit for a concealed weapon.

“I approached him and everything kind of went down,” Danny Thomas, the victim’s boyfriend, told the Santa Cruz Sentinel. “He shot the gun off a couple of times, and I bit part of his ear off.”

The gunman's father, Ronald Goulet, told the newspaper that his son had an affinity for guns.

"He's always had guns. He likes to go target shooting and stuff like that. More of a collector," he said, adding that his son had never been in trouble over the firearms and was never violent.

"He's never been convicted of a felony," the elder Goulet told the San Francisco Chronicle. “"He does have guns -- he's a collector and he does target practice. But I don't think he's going to be shooting anyone."

Jeremy Goulet reportedly sent a text on Tuesday afternoon to his twin brother, Jeffrey Goulet, telling him he was in trouble.

“Why was he on the run? I'm just trying to hang with it, to make sense of it," his father told the Chronicle.

An unidentified woman who said she was a former roommate of Goulet's said he had “some anger issues.”

"He'd have his brother stay and they'd get in huge arguments," she told the Santa Cruz Sentinel.