Mayor Lori Lightfoot suffered a public embarrassment Wednesday that could hamper her efforts to establish a dialogue with the Fraternal Order of Police she needs to negotiate a new police contract.

It happened as the second vice-president of the Fraternal Order of Police was speaking during the prelude to the City Council meeting.

As Patrick Murray spoke, Lightfoot was picked up by a live microphone calling him “this FOP clown.”

Murray was there to defend the four Chicago Police officers fired by the Police Board for covering up for Jason Van Dyke, the officer convicted of second degree murder for shooting Laquan McDonald.

He was arguing that “nobody worked together to form a conspiracy” and the four officers got a raw deal from the Police Board.

Lightfoot, who normally listens intently and takes notice during the public comment section, turned to her corporation counsel, Mark Flessner, and said, “Back again. This is this FOP clown.”

The mayor’s off-handed remark was picked up on the livestream of the City Council meeting.

That’s apparently why the mayor made no attempt to deny the remark during the news conference that followed the council meeting.

“It was not appropriate for me to say that out loud,” Lightfoot said.

Is the mayor planning to apologize to Murray or to the union with which she is now attempting to establish a dialogue and needs to negotiate a new police contract?

“I think I just did. I think I said I shouldn’t have said that out loud,” she said.

Is the mayor sorry she said it or is she sorry the derogatory remark got picked up on a hot mic?

“I’m sorry that I said it out loud,” she said.

The FOP fired back at the mayor on the union’s Facebook page.

“Mayor Lightfoot’s contemptuous remark is a misguided and dangerous thing to say to a 30-year veteran police officer and FOP representative, particularly at a time when the city is facing such chronic violent crime,” the union said.

“It is also telling that the mayor would not even apologize. The red noses, however, belong on the members of the Chicago Police Board, her former agency, for their despicable decision to fire three police officers and a sergeant last week for no good reason whatsoever.”

It was the second time that Murray had confronted Lightfoot.

At the June 12 council meeting, Murray showed up to accuse the new mayor of freezing the police union out of transition discussions on public safety and police reform and got a tongue lashing in return.

“Any time you’re willing to move forward on reform and not block every single issue and criticize and say, ‘No,’ my door is open. I’ve said that to your president. No one’s taken me up on it, sir,” she said to applause.

Murray wasn’t the only one who got a mouthful from the mayor during Wednesday’s public comment section.

So did a speaker who showed up on behalf of 75 murdered South Side women whose deaths, the man claimed, have never been investigated by the Chicago Police Department.

“I need your undivided attention, Mayor Lightfoot. I need your undivided attention,” the man said.

The mayor was livid.

“Sir, proceed with your statement. You don’t stand there as a man and tell me what to do when I was actually getting my notebook to take some notes,” Lightfoot said.

“If you want to talk, talk. You’re wasting your [three minutes of] time. But, don’t ever, EVER tell me what to do when I’m standing here conducting the business of the people. Do you understand that, sir?”

This time, the mayor received an apology, followed by a blast.

“I apologize mayor, but there are families who are mourning, who are grieving, who need justice for their families and I’m here on their behalf because you have failed,” he said.

“You sat here and said you were concerned about the families and you have not launched an investigation and have not called out the serial killers who are in our city. You have not …called the FBI into this city to deliver a message of truth for our people.”