In December, a couple of months after Lt. Bob Kroll, the head of the Minneapolis police union, stood onstage with President Donald Trump at a campaign rally and praised the “wonderful president” for “everything he’s done for law enforcement,” he received a short Facebook message from a disgruntled city resident: “Nazi piece of shit,” the man wrote to him.

Kroll fired off a reply, pointing out his family’s record as defenders of the Allied forces during both World Wars, and then launching into a series of insults: “Keep spewing uniformed [sic] shit from your computer in your moms [sic] basement, loser,” he wrote to the man, according to a report by the Minneapolis City Pages, a local newspaper. “If you hate me so much, why don’t you stop by and beat the shit out of me?…My bet is it won’t happen, because you are a cowardly cunt.”

It might not have been the response you’d expect from a public official who represents 800-plus rank-and-file police officers. But Kroll, who has led the Police Officers Federation of Minneapolis for five years, has a reputation for inflammatory remarks. Now, his brash leadership and influence over the police department’s culture are in the spotlight amid protests over police violence in the city after George Floyd’s death at the hands of a white officer on Monday.