The Capitol rioter who used a fire extinguisher to assault police has been sentenced to five years in prison, becoming the harshest punishment imposed on those who stormed the government building so far.

According to NBC News, on Friday (Dec. 17), U.S. District Judge Tanya S. Chutkan sentenced Robert Palmer to 63 months behind bars for his actions on Jan. 6. “It has to be made clear that trying to violently overthrow the government, trying to stop the peaceful transition of power, and assaulting law enforcement officers in that effort is going to be met with absolutely certain punishment,” said Judge Chutkan.

Palmer was charged with assaulting police officers in the Capitol’s Lower West Terrace. According to prosecutors, the Florida native threw a wooden plank at the police, then grabbed a fire extinguisher and sprayed its contents at the cops. Once it was empty, he threw the canister at them.

A few minutes later, Palmer picked up the fire extinguisher and threw it at authorities a second time. He also assaulted another group of cops with a metal pole. The brutal attack on the officers stopped once he was hit in the abdomen by a rubber bullet. None of the officers he assaulted were seriously injured.

Palmer turned himself into the FBI shortly after the riot occurred. In October, he pleaded guilty to the charges. However, he posted on social media that he acted in self-defense and only threw the fire extinguisher after he was shot with the rubber bullet. Judge Chutkan said his posts showed a lack of remorse.

“Those officers were so brave standing there, just taking all the stuff that people were giving them, all the taunts, all the jeers and everything,” Palmer told the judge prior to being sentenced.

“I am so ashamed I was part of that. Very, very ashamed,” he added.