An undercover New York City police detective who was among a group of motorcyclists chasing a sport utility vehicle on the West Side of Manhattan last month was arrested on Tuesday evening for his role in the episode, in which the vehicle was damaged and the driver was beaten, the police said.

The detective, Wojciech Braszczok, 32, was off duty at the time, and had told his lawyer that, while he had followed the motorcyclists from the Henry Hudson Parkway onto a Washington Heights street, he left once some of the riders began attacking the vehicle.

But investigators found his story suspicious from the beginning — in part because the detective took several days to come forward after the violent and chaotic episode on Sept. 29, said a law enforcement official, who spoke only on the condition of anonymity because the detective had not yet been arraigned.

Detective Braszczok’s story was contradicted, the official said, by video taken at the scene, as well as by witness statements. In the video, the detective can be seen pounding his fists on the back of the vehicle.