An undercover police officer was arrested Tuesday after allegedly lying to police about his involvement in last month's biker attack of an SUV in New York City.
Wojciech Braszczok, 32, was charged with riot and criminal mischief.
The veteran detective originally told police he didn't arrive until after the attack on Alexian Lien. However, video viewed by the NYPD told a different story.
Video shows the undercover officer was involved, as he can be seen banging on the window of the Range Rover, unnamed police sources say.
"It shows him punching the back window," an unnamed source said. "And then as the camera is moving it catches him maybe throwing a kick at the side of the car."
After Lien was pulled from the SUV, the undercover officer is then seen riding away. Lien was then beaten in front of his wife and daughter by the bikers.
Prior to the savage beating, the motorcyclists had followed the vehicle up New York's West Side Highway after it clipped one of their fellow members.
NYPD Commissioner Ray Kelly said the officer, who waited days before coming forward, had been placed on modified duty pending an internal investigation.
He turned himself in and was taken to Manhattan Central Booking. The undercover officer was unarmed and was not carrying a badge during the attack.
The rules for undercover officers when it comes to reporting crimes are vague.
Undercover officers are required to report being a witness to a crime. Uniformed officers are required to take police action if they see a crime occurring.
The rules are murkier for undercover officers who face blowing their cover, confusing civilians and potentially ruining lengthy and expensive investigations.
"Compromising his identity could compromise all the work he's doing and his safety," Michael Palladino, president of the NYPD detectives union, said.
"It's very difficult to lead a double life."
Four bikers have been formally charged in the SUV assault so far, and police are seeking at least two other suspects in conjunction with the case.