(NBC NEW YORK) -- Prosecutors upgraded charges to include gang assault for an undercover NYPD officer who was allegedly involved in

a violent fight between a group of motorcyclists and a man driving a Range Rover

in Manhattan.

Detective Wojciech Braszczok, 32,turned himself in to police Tuesday evening and was initially chargedwith riot and criminal mischief, according to police. The upgradedfelony charge was added Wednesday.

He's not believed to have physicallyassaulted the driver, who was pulled from the SUV and beaten after beingchased by the bikers; he is charged with assault because he wasallegedly part of the larger group that carried out the attack.

Braszczok, who was not on duty, wasseen on video wearing a black vest that said "Front Line Soldiers" onthe back,punching the SUV, shattering its rear window, and then kickingthe passenger side door, according to the criminal complaint.

At court for his arraignmentWednesday, his lawyer John Arlia said the video shows he wasn't part ofthe assault and that the charges are not deserved.

Braszczok has spent 10 years with the NYPD, the last five as an undercover, including during theOccupy Wall Street movement, according to a law enforcement official.

During his time with Occupy WallStreet, he participated in demonstrations, attended meetings andessentially lived like a protester to provide information to the NYPD,according to the official.

Braszczok came forward last week,several days after the Sept. 29 chase that ended in a fight, to say hewas present, according to a source, and did not call 911 when theassault was taking place.

The video that just recently surfacedshows the undercover riding off when the driver is pulled from the SUV,according to a person familiar with the investigation. The video hasnot been made public.

Sources say Braszczok was not truthful with investigators about his role.

NYPD Commissioner Ray Kelly saidTuesday that a detective had been placed on modified duty and that hisinvolvement is under investigation.

Undercover officers are required toimmediately report being a witness to a crime. Uniformed officers arerequired to take police action if they see a crime occurring, but therules are murkier for undercover officers who face blowing their cover,confusing civilians who don't realize the undercover is really a cop andruining years-long investigations.

It is not clear why Braszczok was riding with the group of motorcyclists.

On Wednesday, another biker, JamesKuehne, 31, of Brooklyn, was arrested in connection with the melee andcharged with gang assault, criminal mischief and criminal possession of aweapon.

Six bikers aside from Braszczok have now been criminally charged.