NEW YORK (CBSNewYork) — An NYPD officer was caught on camera punching a man and pointing a gun at bystanders, and some witnesses believe his actions were excessive.

As CBS2’s Valerie Castro reported, the NYPD said the officer – seen on video pointing his gun at onlookers while he tries to arrest a suspect – is now on modified assignment while the department investigates.

“When I saw the gun, I think my heart raced a little bit. Raced a little bit – I’m like: ‘Is he going to shoot? Is he really going to shoot right now? I hope he doesn’t shoot right now,’” said witness Ronnie Pinkerton Jr.

Pinkerton saw what police sources said was the takedown of a man wanted for possessing an illegal dirt bike. It happened Thursday afternoon at the housing development at 480 St. Nicholas Ave. in Harlem.

Pinkerton said the crowd believed the officer was using excessive force in the arrest.

“He has him in a headlock between his legs, so his head is between his legs and he’s kind of like squeezing, so as he’s doing that, he’s telling us to back up,” Pinkerton said. “But you’re overreacting, you’re using too much physical strength on him, so we’re telling him, ‘You’re wilin’; you’re bugging out.’ So he pulled out his gun and says, ‘Back up! Back up! Back!’”

Moments later, Pinkerton said the officer followed the crowd outside, and punched Pinkerton’s friend in the face.

“He acted like he was looking somewhere else, so as soon as he walked out, he hit him, grabbed him, threw him down to the floor,” Pinkerton said.

Pinkerton said he started recording a video of the takedown.

“This is after they punched him and brought him down to the ground, so you can hear him say, ‘Call my mother!’” Pinkerton said. “The officer has his knee in his back, and the captain is on him, too.”

Pinkerton said he is still surprised by what he witnessed with his own eyes.

“It’s just another example of how police can honestly do whatever they want and get away with it, how I feel personally,” he said.

Pinkerton said his friend who was punched in the face in the video was not charged with a crime and was later released from custody.

The officer was stripped of his badge Saturday pending the investigation.