Paul J. Browne, the Police Department’s chief spokesman, said that the department’s Internal Affairs Bureau was investigating Mr. Campbell’s claims.

Mr. Campbell said that his contact with the police began about 3 a.m. when two officers arrived at his building and asked him to turn down the music inside his apartment, where about 80 people had gathered for what his lawyer described as a gay pride party.

Mr. Campbell, who said he went downstairs to speak with the officers, said he agreed and told some friends who had been on the sidewalk in front of his building to leave or go upstairs with him.

About five minutes later, Mr. Campbell said, he looked at a video monitor in his apartment and saw that the two officers downstairs had been joined by others. A videotape showed the officers appearing to rattle the handle of the front door. After one officer appeared to point to a video camera, a sergeant was seen reaching toward the camera’s lens and apparently turning it away from the stoop.

At that point, Mr. Campbell said, he became concerned and went downstairs to speak with the sergeant. As he approached the front door, he said, he could hear people banging on it from outside. When Mr. Campbell opened the door, one officer pushed the door all the way open and several others poured into the entryway, with one officer shouting “get him,” he said.