U.S. Capitol riot police officers stand guard during a rally in support of defendants being prosecuted in the January 6 attack on the Capitol, in Washington, U.S., September 18, 2021.
U.S. Capitol riot police officers stand guard during a rally in support of defendants being prosecuted in the January 6 attack on the Capitol, in Washington, U.S., September 18, 2021. Reuters / JIM BOURG

A former New York City police officer was found guilty on Monday of assaulting a Washington, D.C., police officer during the Jan. 6, 2021, riot at the U.S. Capitol by supporters of then-President Donald Trump, handing prosecutors another win at trial, a Justice Department spokesman confirmed.

A federal jury in the District of Columbia rejected arguments by Thomas Webster, 56, that he was acting in self-defense when he struck a Washington officer with a flagpole and tackled him.

A spokesman for the U.S. Attorney's Office said Webster will be sentenced on Sept 2.

Webster was the fourth Capitol riot defendant to take his case to a jury trial. The Justice Department has secured convictions in all four of those cases.

Of the four defendants to face a jury so far, Webster was the first to argue he was acting in self defense.

Webster took the witness stand during the week-long trial. He told jurors that the officer had "incited" him by hitting him in the face.

"I felt like I was dealing with a rogue cop," Webster testified during the trial.

Prosecutors had rejected Webster's defense and portrayed the District of Columbia police officer, Noah Rathbun, as the victim in the altercation.

Prosecutors said Rathbun made physical contact with Webster to create distance between the two men, who were on opposing side of a police barricade eventually overrun by Trump supporters.

About 800 people are charged with a role in the Capitol riot, which disrupted a joint session of Congress to certify Joe Biden's presidential election victory and sent lawmakers scrambling for safety. About 250 have pleaded guilty so far.