The man accused of opening fire at a Molson Coors plant in Milwaukee on Wednesday — killing five co-workers and himself — was a gun-loving electrician who had been in a long-running dispute with a co-worker, according to a report.

Anthony Ferrill, 51, had frequently argued with one of the fatally shot victims, a fellow electrician, an employee told the Milwaukee Journal Sentinel.

The two co-workers had accused each other of going into each other’s offices and tampering with computer equipment or swiping tools, the source, who didn’t want to be named, told the outlet Thursday.

Ferrill also often watched movies on his phone during the day, something the other electrician had taken issue with, and believed he was being discriminated against because he was African American, the source added.

Ferrill had been fired earlier in the day but returned to the campus with a stolen name tag and a silenced gun, according to WBBM-TV.

He had worked as an electrician for more than 20 years — including about 17 at the Milwaukee brewery, according to the Sentinel, which cited multiple sources and online employment records.

But the experienced tradesman had started to become paranoid at work, allegedly telling co-workers about a year ago he thought his bosses were breaking into his house, bugging his computer and rearranging his furniture.

“I was, ‘Are you serious, Anthony? What?'” the unnamed employee told the Sentinel. “We all kind of joked about it, saying we should maybe get him an aluminum hat. But he was dead serious about it.”

Neighbors told the outlet that Ferrill was known to carry guns. Some said he always carried a gun and one said she once saw what she believed to be a gun safe delivered to his house, where he lived with his wife and daughter.

Still, he was “a very good electrician,” said Phillip Rauch Sr., who worked with Ferrill for 15 years at the brewery.

“Every time I worked with him, he was always in a good mood,” Rauch, who retired in April, told the Sentinel.