A retired New York City cop has been convicted of assaulting a D.C. officer during the January 6th riot at the U.S. Capitol.

Thomas Webster, a veteran of the NYPD for two decades who served on Mayor Michael Bloomberg’s security detail, was convicted of six counts on Monday by a federal jury, including a felony assault charge that carries up to 20 years in prison.

He is the first of roughly 150 defendants charged with assaulting an officer to make his case before a jury.

Webster, a 56-year-old resident of Goshen, New York, claimed he was acting in self-defense during footage of the beating of a D.C. police officer that earned him the social media moniker “eye-gouger.”

The trial included a wealth of video evidence showing Webster, a former Marine, emerging from a mob of Trump supporters and pushing a metal barricade into a phalanx of cops while shouting curses.

After one Capitol officer, Noah Rathbun, pushed him back with an open hand, Webster slammed the flag pole down on the barricade, then charged forward and tackled the officer to the ground. Rathbun later testified that Webster attempted to remove his face shield and gas mask, choking him in the process.

Federal prosecutors said Webster’s attack was among the most vicious displays against law enforcement during the deadly attack on the Capitol.

“He goes after that cop like a junkyard dog," Assistant U.S. Attorney Ben Gianforti said at one hearing. "Teeth bared. Fists clenched."

During the trial, Webster claimed he was responding to “imminent danger,” alleging Rathbun had escalated the situation by pushing him and “inviting him to engage in a fight.”

“Reasonably believing that he was in danger of imminent serious bodily harm and being unable to retreat due to the large crowd, [Webster] used that amount of force he reasonably believed necessary to protect himself,” his attorneys wrote, according to court documents.

The jury rejected that argument after just a few hours of deliberations on Monday.

Webster is scheduled to be sentenced on September 2nd. Inquiries to his attorneys were not immediately returned.