A United States man accused of using a stun gun against Metropolitan Police officer Michael Fanone has pleaded guilty to his role in the Capitol attack on January 6, 2021.

Daniel “DJ” Rodriguez, a 40-year-old from Fontana, California, submitted his decision to a US District Court on Tuesday, becoming one of nearly 500 individuals to enter a guilty plea for taking part in the riot at the US Capitol building, led by supporters of then-President Donald Trump.

More than 985 defendants have been arrested so far in relation to the January 6 attack, according to estimates from the US Justice Department. Rodriguez was faced with four federal charges, including conspiracy, obstruction of an official proceeding, obstruction of justice and assaulting a law enforcement officer.

He is alleged to have played a central role in the attack on Fanone, a law-enforcement officer who has since become a prominent figure outspoken about the violence that unfolded that day.

On the second anniversary of the attack last month, Fanone was among the 14 individuals to receive the Presidential Citizens Medal from current President Joe Biden, the second-highest civilian award in the US.

Fanone said he suffered a heart attack and brain injury as a result of the Capitol riot, which saw Trump supporters attempt to disrupt Congress’s certification of the 2020 presidential election results.

Rodriguez had previously admitted to using a stun gun on Fanone in an interview with the Federal Bureau of Investigation (FBI), after he was arrested in March 2021. But lawyers for the defence attempted to bar Rodriguez’s words from being used in court, claiming the FBI used “psychologically coercive tactics” to get their client to talk.

Prosecutors said that, in the autumn before the Capitol attack, Rodriguez and others organised a group chat on the encrypted messaging service Telegram. They named the forum “Patriots 45 MAGA Gang”, a reference to Trump – the 45th president – and his slogan “Make America Great Again”, abbreviated as MAGA.

There, Rodriguez was among those posting about plans to attend the January 6 Stop the Steal rally in Washington, DC, where Trump was scheduled to speak. The then-president had been spreading the false claim that his defeat in the 2020 election was due to “rigged” results and fraud.

The rally was set for the same day as Congress’s certification of the Electoral College votes, showing Democrat Joe Biden to have won the presidency.

“Congress can hang. I’ll do it. Please let us get these people dear God,” Rodriguez is alleged to have posted in the group chat. On the day before the Capitol attack, prosecutors say he wrote: “There will be blood. Welcome to the revolution.”

On January 6, Rodriguez is alleged to have walked from the rally down Pennsylvania Avenue, arriving at the lower west terrace of the Capitol.

Faced with police officers, Rodriguez is said to have “participated in a ‘heave ho’ effort with other rioters” to make his way through barricades and into a tunnel where a door into the Capitol was located.

While trying to breach the door, prosecutors say he threw a flagpole and sprayed a fire extinguisher at law enforcement.

In the midst of the melee, officer Fanone was pulled from the police line and dragged into the crowd. Rodriguez, who had been supplied with a “small, black electroshock weapon” by another rioter, allegedly used the stun gun twice on the back of Fanone’s neck.

“Because I was among the vastly outnumbered group of law enforcement officers protecting the Capitol and the people inside it, I was grabbed, beaten, Tased all while being called a traitor to my country,” Fanone later testified before a now-disbanded committee in the US House of Representatives charged with investigating the Capitol attack.

“I was at risk of being stripped of and killed with my own firearm, as I heard chants of, ‘Kill him with his own gun.’ I can still hear those words in my head today,” Fanone said.

After Tasing Fanone, Rodriguez is accused of breaking a window as he entered the Capitol, rifling through offices and congressional papers to look for “intel”. Prosecutors also say he wrote an update in the group chat after encountering Fanone: “Tazzzzed the f*** out of the blue,” a reference to the police.

Rodriguez has since expressed remorse for his actions, telling FBI agents after his arrest that his actions were “stupid”. In the FBI interview, he also explained he sincerely felt he was doing the “right thing” to “save the country”.

Others accused in Fanone’s beating have likewise faced federal charges and lengthy sentences. A man named Albuquerque Cosper Head received a prison term of more than seven years for allegedly pulling Fanone by the neck into the crowd of rioters. Another defendant, Kyle Young, received seven years and two months for his part in Fanone’s assault.

Rodriguez is scheduled to appear before US District Court Judge Amy Berman Jackson in May to receive his sentence.