MILTON, Mass. (AP) — Police say the owner of a Milton mansion that was the site of a massive pool party attended by as many as 1,500 guests is facing charges for selling alcohol without a license.

Police say it took them almost two hours to break up the Sept. 1 party at the home of Steve Mathieu that was advertised on Twitter as the ‘‘Make It Nasty Mansion Pool Party,’’ and charged guests a $15 to $20 cover charge. He also allegedly sold alcoholic drinks without a permit.

Police say the party was a public safety threat because an estimated 350 to 400 cars that clogged neighborhood streets and could have made it difficult for emergency vehicles to get through.

The party was billed as a ‘‘fundraiser.’’