The NYPD’s Civilian Complaint Review Board is reviewing video footage that shows an officer beating a teenager who allegedly had stolen a bicycle in the Bronx, officials said Saturday.

The video shows the officer mounted on the back of the 16-year-old boy who, moments earlier, had knocked down another officer and had his hand around that cop’s throat, police said.

The incident began when the alleged thief, Alfred Burns, tried to swipe a bicycle in front of a store at the corner of 225th and Broadway in the Marble Hill section of the Bronx on Friday morning around 9 a.m., police said.

The shop’s owner chased Burns and alerted nearby officers, police said.

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According to police, Burns knocked down the first officer who approached him and had his hand around his throat.

That’s when the officer’s partner is seen on cellphone video mounting the teen from behind and repeatedly swinging his fist into the back of Burns’ head. The officer has his arm around Burns’ neck while he swung with the other hand as witnesses screamed, the video shows.

A third officer then comes by to help handcuff Burns, the video shows.

Burns was later arrested and charged with assault with an intent to cause injury to an officer in the second degree, resisting arrest, criminal possession of stolen property in the fifth degree, petit larceny, obstruction of governmental administration in the fourth degree and assault with intent to cause injury, court records show.