WASHINGTON (AP) — A leader of the far-right Proud Boys extremist group was arrested Tuesday on a conspiracy charge for his suspected role in a coordinated attack on the Capitol to stop Congress from certifying President Biden’s 2020 electoral victory.

Henry “Enrique” Tarrio wasn’t there when the riot erupted on January 6, 2021. Police had arrested Mr. Tarrio in Washington two days before the riot and charged him with vandalizing a Black Lives Matter banner at a historic Black church during a protest in December 2020. The day before the Capitol was attacked, a judge ordered Mr. Tarrio to stay out of Washington.

But Mr. Tarrio didn’t leave town as he should have, the indictment said. Instead, he met with Oath Keepers founder and leader Elmer “Stewart” Rhodes and others in an underground parking garage for approximately 30 minutes.

“During this encounter, a participant referenced the Capitol,” the indictment says.

Mr. Tarrio made his initial court appearance via video link to a Miami courtroom Tuesday. His detention hearing was scheduled for Friday.

The arrest came as federal prosecutors won a conviction on all counts in the first trial for a rioter since the attack.

The indictment is further proof of how far the Justice Department is going to prosecute the leaders of extremist groups whose members are suspected to have planned and attacked the Capitol, even if they weren’t in attendance themselves. 

The latest conspiracy charge zeroes in on organized groups that plotted in advance — as federal prosecutors distinguish them from hundreds of other supporters of President Trump who were at the scene that day and were charged.

The new riot-related charges are among the most serious filed so far, but they aren’t the first of their kind. Eleven members or associates of the antigovernment Oath Keepers militia group, including Mr. Rhodes, have been charged with seditious conspiracy in the Capitol attack.

A message left for Andrew Jacobs, an attorney appointed to represent Mr. Tarrio, wasn’t immediately returned Tuesday afternoon.

Phillip Linder, an attorney representing Mr. Rhodes, also didn’t immediately return a call seeking comment on his client’s behalf.

Mr. Tarrio, who has since stepped down from his post as Proud Boys chairman, didn’t immediately respond to a text message seeking comment on his arrest and indictment. He served five months for the unrelated case.

On December 30, 2020, an unnamed person sent Mr. Tarrio a document that laid out plans for occupying a few “crucial buildings” in Washington on January 6, including House and Senate office buildings around the Capitol, the indictment says. The nine-page document was entitled “1776 Returns” and called for having as “many people as possible” to “show our politicians We the People are in charge,” according to the indictment.

“The revolution is important than anything,” the person said.

“That’s what every waking moment consists of … I’m not playing games,” Mr. Tarrio responded, the indictment says.

Proud Boys members describe the group as a politically incorrect men’s club for “Western chauvinists.” Its members frequently have brawled with antifascist activists at rallies and protests. Vice Media co-founder Gavin McInnes, who founded the Proud Boys in 2016, sued the Southern Poverty Law Center for labeling it as a hate group.

On the morning of January 6, group members met at the Washington Monument and marched to the Capitol before Mr. Trump finished speaking to thousands of supporters near the White House.

Just before Congress convened a joint session to certify the presidential election results, a group of Proud Boys followed a crowd of people who breached barriers at a pedestrian entrance to the Capitol grounds, an indictment says. Several Proud Boys also entered the Capitol building itself after the mob smashed windows and forced open doors.

Prosecutors have said the Proud Boys arranged for members to communicate using specific frequencies on Baofeng radios. The Chinese-made devices can be programmed for use on hundreds of frequencies, making them difficult for outsiders to eavesdrop.

More than three dozen of the more than 750 people charged in the Capitol siege have been identified by federal authorities as Proud Boys leaders, members or associates.

A New York man pleaded guilty in December to storming the Capitol with fellow Proud Boys members. Matthew Greene was the first Proud Boys member to publicly plead guilty to conspiring with other members to stop Congress from certifying the Electoral College vote. Mr. Greene agreed to cooperate with authorities.

In December, a federal judge refused to dismiss an earlier indictment charging four alleged leaders of the far-right Proud Boys with conspiracy. District Judge Timothy Kelly rejected defense attorneys’ arguments that the four men — Ethan Nordean, Joseph Biggs, Zachary Rehl and Charles Donohoe — were charged with conduct that is protected by the First Amendment right to free speech.

Messrs. Nordean, Biggs, Rehl and Donohoe remain jailed while awaiting a trial scheduled for May.

Mr. Tarrio tried to communicate with Messrs. Nordean and Biggs by telephone while the two men were moving in and out of the Capitol, the indictment says. Messrs. Biggs and Tarrio had a 42-second call just before 3 p.m. on January 6, according to the indictment.

Mr. Nordean, of Auburn, Washington, was a Proud Boys chapter president and member of the group’s national “Elders Council.” Mr. Biggs, of Ormond Beach, Florida, is a self-described Proud Boys organizer. Mr. Rehl was president of the Proud Boys chapter in Philadelphia. Mr. Donohoe, of Kernersville, North Carolina, also served as president of his local chapter, according to the indictment.

Dominic Pezzola, 44, of Rochester, New York, also is charged with Mr. Tarrio in the new indictment, which identifies Mr. Pezzola as a member of his local Proud Boys chapter. Mr. Pezzola already was charged with conspiracy in a separate case and has been jailed since his arrest. Mr. Greene traveled from Syracuse, New York, to Washington with Mr. Pezzola and other Proud Boys on January 5, according to prosecutors.