NEW YORK (CBSNewYork) – The NYPD is trying to track down a cyclist behind a bizarre attack against an Uber driver last week in Midtown.

Police said the cyclist tracked down the driver, smashed his window and struck him in the head with a bike lock – while there were passengers in the backseat.

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It started around 1:20 p.m. last Friday when the suspect alleged started banging on the driver’s window, investigators said. The driver tried to turn onto East 40th Street near Fifth Avenue, but the suspect followed him.

While the Uber was stopped in traffic, the cyclist allegedly used his lock to smash the car’s front windshield and shatter the rear window. When the driver exited his car, police said the suspect hit the 23-year-old in the head and back with the lock.

Video shows the cyclist them climb on top of the car, screaming and stomping on the hood, before he took off heading west on East 40th Street on a black and green bike.

(Credit: NYPD)

The driver was taken to the hospital and treated for cuts. His passengers were not hurt.

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Witnesses told CBS2’s Scott Rapoport the driver was badly beaten and tried to fight back.

“The driver tackled the guy, he let the guy up, and the guy rode away on his bike,” said Tom Scarry.

“Ambulances all over the place, police, smashed up windshield, his head all covered and bleeding,” Dmitri Sebastian added.

It’s unclear exactly what led up to the attack, but NYPD Chief of Detectives Dermot Shea said it appeared to be unprovoked.

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Anyone with information about the attack is asked to call the NYPD’s Crime Stoppers hotline at 1-800-577-TIPS (8477), or 1-888-57-PISTA (74782) for Spanish. The public can also submit their tips by logging onto the Crime Stoppers website, on Twitter @NYPDTips or by texting them to 274637 (CRIMES) then enter TIP577.