punched by a fellow trooper back in June at a Marina Bay pub in Quincy.

A Massachusetts state trooper is now facing an assault charge for allegedly pummeling one of his colleagues at a Quincy bar this June, and a police report offers new insight on what happened in the incident, seen in a viral video.

The trooper who was punched several times declined to press charges when officers arrived at the Reelhouse Marina Bay late on June 26, according to the police report. Neither trooper responded to a Quincy police lieutenant's requests to speak about the incident, nor did a woman who was with them.

The NBC10 Investigators obtained the police report after learning on Wednesday that Trooper Christopher Regan, the officer accused of hitting the other, declined what's known as a "show cause" hearing, where a clerk magistrate would hear evidence and decide if charges should be brought in court. Those hearings are typically held behind closed doors, but NBC10 Boston and the Boston Herald had successfully petitioned for Regan's, set for next week, to be public.

The NBC10 Investigators have uncovered new information about a Quincy bar fight seen in a viral video, in which a man punches another several times — both are off-duty Massachusetts State Police troopers, and one now faces an assault charge.

Regan will instead be arraigned on a charge of assault and battery in Quincy District Court next month, a court clerk told NBC10 Boston.

Regan was suspended with pay after the incident, and state police have said the agency’s Office of Professional Integrity and Accountability is investigating the incident involving the two off-duty troopers, which it described as “serious and inconsistent with the standards required of every member of the Department.”

Regan and the other trooper were also reassigned from their detective posts in the Suffolk District Attorney's office to the Division of Field Services, according to state police.

State police said Friday that Regan remains suspended with pay and the other trooper remains on full duty for the Division of Field Services.

"The Department will monitor the ongoing criminal proceedings and await the outcome before completing its internal affairs investigation," a spokesperson wrote in an email to NBC10 Boston.

Trooper Christopher Regan is facing possible criminal charges after allegedly punching a colleague in an incident caught on camera.

The surveillance video went viral after the online site “What’s the Word Mass” posted the footage on its social media accounts in June.

The video shows a man pummeling another patron at a Quincy bar with a series of punches. The blows appear to knock out the victim as a bartender covers her mouth in the background.  

Two employees of the bar who can be seen in the video told Quincy police that they could sense the conversation between the troopers getting tense before the punches were thrown, according to the police report. A barback went to get the manager and the bartender — who'd served both troopers before and said the group had spent about an hour having a friendly conversation — tried to defuse the tension.

Surveillance video shows a man pummeling another patron at a Quincy bar, apparently knocking out the victim as a bartender covers her mouth. Massachusetts State Police has said the two men are troopers who were off-duty at the time.

She recalled saying, "Hey buddy what's going on, relax," according to the report, because Regan was evidently upset about something, though she didn't know what it was. She said the other trooper tried to deescalate things before Regan got up and punched the man multiple times.

Reached Wednesday, the bartender declined to comment to NBC10 Boston about what happened.

The woman who'd been with the two troopers — the bartender recalled to police her being at the bar with the other man before Regan joined them — didn't respond to the lieutenant's request to discuss what happened, the police report said.

The union representing state troopers has previously told NBC10 Boston that Regan will be getting his own attorney to address the matter.

Massachusetts State Police did not release the trooper's name, saying only they were immediately relived of duty after the department learned of the incident.