"While a full investigation is still underway, there is no question in my mind that this immediate action is necessary," Shea said Sunday.
The NYPD's Internal Affairs Bureau launched an active use of force investigation after video of an arrest surfaced on social media.
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An attorney for the man seen in the video has called for the officer involved to be fired and prosecuted.
The video shows several officers affecting the arrest of an individual, with one in particular appearing to put him in a chokehold.
Another officer is observed tapping the back of the officer who had the individual in an apparent chokehold, and that officer appears to release his hold.
Body camera released by the NYPD shows the moments leading up to the incident.
According to a law enforcement source, the incident happened 8:45 a.m. Sunday morning on Rockaway Beach Queens boardwalk as police were responding to a disorderly group in the area.
Three men in particular are seen on camera making exchanges with police, sometimes in conversation, other times name calling and taunting.
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At one point the man who eventually was taken into custody approaches the officers and taunts them, saying "I'll throw sh*t in your face."
The law enforcement source described the man saying on camera "touch any of my boys and you'll be dead," parts of which can be heard on camera.
It's at this point one of the other men intervenes and says "stop," while a third man says you're just "givin' them a reason to beat our a**es."
One of the men has a cell phone on the police the whole time, continuing to taunt them and call them names, and shouting out the officers' names and badge numbers. He named one officer repeatedly and challenged the officer to "push" him again.
A few times the officers tell the individual that they are too close. At least one officer is observed wearing a mask, a requirement in the pandemic.
After about 10 minutes into the video, one man reaches down and pulls up a plastic bag. He then walks out of view of the camera and his friend asks him, "What are you doing?" Then the officers proceed to move in for arrest.
'He's choking him'
A scuffle ensues and the video shows several officers working to arrest the man -- from the view of the body camera you can see an officer eventually remove his arm from the man's neck.
"He's choking him," you hear from bystanders, even as officers are walking him to their vehicle. When asked by another bystander, an officer says, "He's not getting arrested, he's going to the hospital."
Eventually you see the suspect walking in handcuffs with police.
The man, whose name has not been released, suffered a laceration and was taken to a nearby hospital, the source said, adding that the man is still in custody and charges have not yet been announced or filed.
Queens District Attorney Melinda Katz said in a statement Sunday that her office is aware of the incident and that an investigation is underway.
"There must be zero tolerance for police misconduct. The District Attorney's Office is aware of the incident in Far Rockaway today. We take these allegations very seriously and an active investigation is underway," Katz said.
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Attorney for man in "apparent chokehold" calls for officers firing
An attorney representing the unnamed man seen in the video has called for the officer involved to be fired.
Lori Zeno, executive director of the Queens Defenders, said the NYPD officer used a chokehold to strangle her client until he was unconscious. "This officer needs to be fired and prosecuted. He is the one who committed a crime in this circumstance," Zeno said.
She said her client has been charged with disorderly conduct, obstructing governmental justice, and resisting arrest.
Speaking to a crowd outside NYPD's 100th precint Sunday, Zeno said that officers approached her client "because he was kicking cans" and several officers "pounced" on her client after he allegedly kicked a can to an officer.
"The third charge, which is almost comical to be honest with you given his size and that three officers were on top of him, resisting arrest," Zeno said. "Resisting arrest, exactly. He couldn't even move. Right."
She said her client also suffered a "big circle on the back of his head" where his hair came off, causing a bloody scalp.
Sweeping police reform bills passed
The Civilian Complaint Review Board, the city agency charged with oversight of the NYPD, is also opening up an investigation, according to a city official.
The New York City Council last week passed a sweeping package of police reform bills, including an official ban on chokeholds. It has not been signed by the mayor.
The body camera footage was released as part of new directives put in place by Mayor Bill de Blasio last week.
A spokesperson for de Blasio's office said Sunday that "The video is very concerning. We're glad the NYPD is immediately launching an investigation to get to the bottom of what happened."
CNN is working to obtain permission of the bystander video, which has been posted on social media by several people, including a councilman candidate.
CNN has reached out to the Police Benevolence Association, the NYPD's union, and is working to reach the lawyer for the man arrested.