Chicago Police have cited the owner of a townhome that was the site of a large house party over the weekend, according to a Northwest Side alderman.

Ald. Gilbert Villegas (36th) said he convened a Monday meeting between the building owner and the commander of the CPD’s Grand Central District, who issued the woman “a couple citations for public nuisance and gave her strict warnings and we also have just put her on notice.”

Video footage of the weekend party in the 2000 block of North Narragansett quickly went viral. Clips posted to Facebook showed dozens of people crammed into the home, with everyone standing in very close proximity and hardly anyone wearing protective masks.

Villegas — Mayor Lori Lightfoot’s floor leader in City Council — said the party was the doing of the building owner’s adult son. The owner’s son had a set of keys to the building and was able to disarm the home’s alarm system. It was the second party he’s thrown in the building in recent weeks, Villegas said.

The home, in Chicago’s Galewood community, is in Villegas’ ward.

Earlier in the day, Lightfoot vowed to “get to the bottom” of the party — and hold everyone involved accountable for the public health risk.

Lightfoot said the city is “still in the midst of the investigation to identify the specific location” of the party, captured on a shocking Facebook video that already had been viewed more than a million times before it was taken down Monday.

The party is believed to have taken place somewhere on the West Side, but City Hall is still “nailing down specifics,” she said.

The mayor argued “everybody involved” in the party “bears a level of responsibility” and will ultimately be held accountable.

“When you see a scene like that where you have, literally, it looked to me, like hundreds of people gathered in a small, confined space literally cheek-to-jowl like that, it goes against all of the things we’ve been talking about. All of the things that the vast majority of Chicagoans understand and know,” the mayor said.

“They put themselves at risk. But not only that. Every single person there who put themselves at risk puts the next person and the next person that they come into contact with at risk. That’s why, for me, that scene is so distressing. But, we’ll get to the bottom of it.”

Lightfoot pointed to “Zoom chats” and other opportunities for young people to connect using social media. She said the city plans to “step up and do a lot over the course of the summer, depending on where we are in the arc of this virus” and how much the stay-at-home order is relaxed. But she argued a shortage of organized teen activities is no excuse to flout the statewide, stay-at-home order.

“What happened in that scene was just foolish and reckless. There’s got to be a level of personal responsibility for that. Millenials aren’t children. Millenials—many of `em—are in their 20’s. They’re fully functioning adults. And we expect adults to act responsibly—particularly at a time of pandemic,” the mayor said.

Videographer Tink Purcell captured the chaotic Saturday night party scene from halfway up a staircase and streamed it live on Facebook for about 24 minutes.

Some partygoers were wearing face masks, but most were not. Social distancing was out the window as those in attendance danced and drank elbow-to-elbow while lines formed at the front door and on the stairs.

The mayor was asked how she plans to prevent similarly unauthorized house parties as temperatures rise and cabin fever builds.

“I can’t prevent people from being foolish. I wish I had that kind of power. What we can do ... is educate people about why taking those kinds of risks are unnecessary and foolish, talk about personal responsibility and then, where we see it, take decisive action and make sure that we shut it down,” Lightfoot said.

“I have no compunction about setting the appropriate example in egregious situations like we saw. Not just in that event, but there were several other large-scale parties that the police department was called upon to break up over the weekend. We’re not gonna set the standard for the summer and warmer weather by allowing people to flout all the public health guidance we’ve been giving.”