[Ammi]

An undercover police officer has appered in court to face riot and criminal mischief charges after a New York biker brawl.

Wojciech Braszczok was apparently seen on a video hitting and kicking a car whose owner was allegedly attacked by a group of motorcyclists.

The driver, Alexian Lien, was pulled from his Range Rover last month and assaulted after hitting a motorcyclist when a biker rally spiralled into violence

Braszczok's lawyer said the video actually exculpates his client, who was at least 12ft from the attack on Mr Lien, a married father of a toddler whose family was in the car at the time.

But prosecutors say the undercover cop was an "active participant" in the attack.

Braszczok surrendered on Tuesday, according to police.

He was stripped of his gun and badge after internal affairs detectives discovered he was present for at least part of the melee.

NYPD internal affairs investigators had initially been looking into Braszczok's conduct because he did not report until three days later that he had been at the rally.

The expectation that police officers will act if they see crimes is not the same for undercover officers

But Assistant District Attorney Samantha Turino said Braszczok should have stepped in to try to stop the attack.

The encounter, captured partly on a helmet-mounted video that was posted online, began when about two dozen riders slowed down, swarming the SUV after it bumped a biker on the West Side Highway.

Some riders dismounted and approached the SUV, and police said some bikers began damaging it.

Mr Lien took off running over motorcyclist Edwin "Jay" Mieses Jr. The impact broke Mieses' legs and caused spinal injuries that may leave him paralysed.

Mr Lien's wife has said he feared for their lives and the safety of their two-year-old daughter and had no choice but to flee. Mr Lien has not been charged with any crime.

The bikers pursued the SUV, which left the highway and got stuck in traffic.

One biker used his helmet to shatter the driver's window, and others pulled Lien out and beat and kicked him, police and prosecutors said. Mr Lien needed stitches.

Six people have been arrested in connection with the attack