A third New York Police Department officer has come forward to admit that he was among the bikers involved in the brutal beating of a motorist two weeks ago that sparked national headlines.

Matthew Rodriguez, a 28-year-old Internal Affairs Bureau officer and five-year veteran of the department, quietly came forward to admit that he was among the off-duty police duty officers present at last month’s bike incident. It was not clear if Rodriguez was involved in the investigation, but his department is responsible for monitoring wrongdoings by police officers.

The NYPD did not respond to a request for comment by local news organization DNAinfo and Rodriguez’s lawyer, Pat Bonanno, said only that Rodriguez has not been charged and is still working full time for the NYPD.

Rodriguez is known as a motorcycle aficionado who recently talked about selling his bike when he moved from the Bronx to upstate New York because his wife did not like it. His Twitter page also features a background image of a man and woman having sex on the back of motorcycle and the phrase "No Free Rides! Gas or [profanity]!"

The IAB officer could face disciplinary measures within the NYPD for failing to come forward sooner, such as obstructing governmental administration and official misconduct. Rodriguez could also be hit with a criminal charge for failing to intervene in the attack that sent the driver of the black Range Rover, Alexian Lien, to the hospital.

Rodriguez’s admission comes as another blow to the NYPD after undercover detective Wojciech Braszczok surrendered to face riot and criminal mischief charges after being videotaped pounding on Lien’s window in the incident.

The arrest added to the complexities of the Sept. 29 episode, which authorities say began with a reckless motorcycle group ride on a Manhattan highway and ended with one motorcyclist run over and the driver dragged from his SUV and beaten on a street.

Six people have been arrested. Four bikers have been criminally charged.

Some of the bikers involved in the accident are claiming that Lien, knowingly or unknowingly, instigated the confrontation off-camera earlier by clipping one of the bikes in a rally on the Henry Hudson Parkway in Manhattan.

Authorities are looking into everything that unfolded along the ride's path from lower to upper Manhattan. Investigators are looking for other helmet-camera videos of the ride, which spurred 911 calls about the bikers' behavior before the SUV driver's beating.

Attorney Gloria Allred, representing Edwin Mieses Jr., the biker who was crushed, claims Lien bumped another motorcycle while changing lanes on the highway two to three miles before his SUV knocked into biker Christopher Cruz.

"We have evidence that he hit that (first) bike and didn't stop," Allred said by phone.

Mieses, of Lawrence, Mass., didn't see any earlier encounter but got off his motorcycle to defuse the tense situation and was headed back when he was hit from behind by the SUV, she said. He broke his legs and suffered a spine injury and likely is paralyzed, his family has said.

Allred declined to say what other witnesses had contacted her, but another biker who participated in the rally, Louis Castaldo, gave a similar account in an interview on Fox 5 News.

Castaldo said that when bikers tried to approach Lien's Range Rover, Lien "decides to run over three or four people. ... He should have just apologized."

Images made public have painted a narrative that begins with Cruz, of Passaic, N.J., pulling in front of the black Range Rover and decelerating to the point where the vehicle bumps his back tire.

Cruz, since his arrest on reckless endangerment and other charges, has insisted he looked over at the driver only to change lanes and didn't deliberately slow down. He didn't see any prior interaction that may have happened between the SUV and the motorcyclists, said his attorney, H. Benjamin Perez. Cruz waited on the highway for police when other riders chased after Lien, Perez said.

"He's treated as though he orchestrated this entire event," Perez said. "It's crazy."

The Associated Press contributed to this report.

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