Surprise, surprise: the off-duty cop charged with gang assault in a motorcycle mob's beating of an SUV driver isn't going to testify. Undercover NYPD Detective Wojciech Braszczok, 32, had previously told prosecutors he would testify in order to share his side of the story with a grand jury, but he now he's clammed up. His lawyer, John Arlia, told the Post, "He’s decided he wants the video to speak for itself."

But investigators say video they've obtained shows Braszczok smashing the rear window of Alexian Lien's SUV, moments before he was dragged out of his Range Rover and beaten in front of his wife and children. Braszczok waited three days before coming forward to tell supervisors he was involved in the illegal group motorcycle ride, which turned violent after Lien clipped one biker and then plowed over another in a desperate attempt to escape.

Arlia tells the Daily News, "My client has complete confidence and faith this grand jury will determine that he in no way intended to injure or acted in any way to injure Mr. Lien. Mr. Lien however drove over and crushed Mr. Mieses' spine, paralyzing him, and then decided to flee the scene." Braszczok, who infiltrated Occupy Wall Street by posing as a protester, is also charged with riot and criminal mischief.

Eight people have now been charged in connection with the incident—last night the NYPD arrested Brooklyn resident Jason Brown, 40, on gang-assault charges. Several other NYPD officers are believed to have participated in the group ride, but they haven't been charged.