NYC Motorcycle Attack Update: Off-duty police officers, including a sergeant, among riders involved in NYC biker-SUV brawl

(CBS) NEW YORK - At least three off-duty police officers say they were part of a motorcycle group involved in the September 29 violent confrontation with a man driving in an SUV with his family on the West Side Highway.

According to CBS News senior correspondent John Miller, a former New York deputy police commissioner, one of the officers riding with the group and who witnessed the violent attack, was an undercover detective. The officer did not intervene in the brawl apparently because he was afraid of revealing his identity.

The undercover detective waited several days before coming forward. It's unclear if the other two off-duty officers also witnessed the beating.

All officers will reportedly be stripped of their guns and badges. They will also be placed on desk duty pending an investigation.

Miller said this case is about when the officers decided to come forward. He explained on "CBS This Morning," "On Wednesday of last week the undercover detective comes forward and says, 'I was there, I saw the beating, I didn't want to break my cover.' He's assigned to the intelligence division and some of the people there are under deep cover and they're training is, even under pressure, you don't admit who you really are. He would be in a lot less trouble if he would [have] come forward the first day instead of four days later."

Miller also said the other two officers that were riding with the bikers include a sergeant and a detective, "That's a supervisor and another of whom is a detective, who is a police officer who is undercover in internal affairs. The irony there is that's the group that enforces police discipline and misconduct have come forward or notified the department about their intention to come forward, and they're going to be sat down and (asked), 'Where were you, what did you see, what did you do, what did you not do, why did you wait to come forward'."

Sorting through the officers' stories is the next step in this investigation, Miller added. "We know of one (officer) who was there at the initial beating, but these other officers, one of the ones that's come forward says after the guy got run over by the SUV, 'I wasn't there for the rest of it.' ... Here's the problem they're going to face, which is whatever they did or didn't do that day is one issue, but not coming forward right away actually could rise to official misconduct for hindering an investigation once they were aware of it and that's a potential criminal charge."

The officers, Miller said, are going to be placed on modified assignments after their stories are weighed. "They could be suspended. This could be grounds for dismissal, this is the D.A.'s call. If the district attorney looks at their conduct and says that rises to official misconduct, 'Everybody knew this investigation was going forward, we needed this information and these guys didn't step forward as law enforcement officers' -- that could be violation of law."

Police arrested two of the alleged assailants over the weekend, and are now looking into two new "persons of interest." More arrests could be on the way.

Police say the man seen pulling the Range Rover's door open is 35-year-old Robert Sims, of Brooklyn. And they say the man who slammed his helmet against the driver's side window is Reginald Chance, 37, also from Brooklyn.

Chance, CBS News has learned, already has 21 prior arrests on his record, including robbery and drug charges. He's a married father of six who has been unemployed since 2011.

Chance's lawyer Gregory Watts admitted that his client overreacted and broke the window, but denied taking part in the beating of Alexian Lien.

Both Chance and Sims have been charged with gang assault and other felonies. Sims, according to court documents, stomped on the head and body of the Lien.

An unknown attacker tried to yank his wife and 2-year-old daughter out of the vehicle.

Witness Sergio Consuegra said, "I heard a lot of people screaming, telling the man -- 'No not the woman! There's a child! There's a child! Not with the child!'"

Police continue to scour the video for clues about the other assailants.

Kevin Bresloff was the motorcyclist who took the video with a high definition helmet camera, his attorney says he is cooperating with police and is not considered a suspect.

Complete coverage of the New York City motorcycle attack on Crimesider