Proud Boys leader Enrique Tarrio was arrested Monday and accused of destroying a Black Lives Matter sign at a historic Black church in Washington, D.C., last month.
Tarrio, chairman of the far-right, all-male self-described group of "Western chauvinists," was taken into custody on suspicion of destruction of property after the incident during a pro-Trump rally Dec. 12 in downtown Washington, police said in a statement.
One of the city's oldest Black houses of worship, Asbury United Methodist Church, said last month that a Black Lives Matter sign was removed from its building and set on fire.
Tarrio, 36, who lives in Miami, was arrested upon entering the city Monday and found to have two high-capacity magazines, police said. He faces an additional gun charge, police said.
More pro-Trump protests are expected in Washington on Wednesday, plans that prompted the mobilization of the National Guard ahead of possible violence.
Separately Monday, Metropolitan African Methodist Episcopal Church sued Tarrio and the Proud Boys in connection with the destruction of a Black Lives Matter sign during the same Dec. 12 pro-Trump rally.
In a complaint filed in D.C. Superior Court, the church accused Tarrio and the group's members of "engaging in acts of terror and vandalizing church property in an effort to intimidate the Church and silence its support for racial justice."
Eight unidentified members of the Proud Boys are also named in the suit.
The incident occurred the night of Dec. 12 after an event that featured right-wing figures like conspiracy theorist Alex Jones and former Trump national security adviser Michael Flynn.
A widely circulated video showed several people destroying a Black Lives Matter sign in front of the church, which was founded in 1872 and hosted Frederick Douglass' 1895 funeral.
In the suit, attorneys for the church alleged that five to eight members of the group leaped over its iron fence, broke the zip ties that held the plastic Black Lives Matter sign in place and joined "in the celebration of the sign's destruction."
In the incident at Asbury, the church's senior pastor said pro-Trump supporters took a Black Lives Matter sign from its walls and "literally burned it in the street."
Metropolitan's attorneys said Tarrio "conspired" with other Proud Boys to plan and promote "violent" events throughout the summer and fall, including on Dec. 12.
The suit cited "countless" messages on social media and other platforms that appeared to encourage members to "buy ammo," "clean your guns" and "keep our enemies awake. Tonight we become nightmares."
The Proud Boys didn't respond to a request for comment Monday. In a post on the social media site Parler, Tarrio said: "You can't put an idea in chains. You can't sue it." He added that the "armor of God protects me."
Last month, Tarrio told local news outlets that he was responsible for burning one of the signs.
"I was the one that lit it on fire," he told DCist/WAMU. Tarrio said he'd been angered to learn that authorities were investigating the incidents as potential hate crimes.
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On a podcast affiliated with the Proud Boys, Tarrio added that he was speaking out against the wishes of his attorney and wasn't ashamed to admit that he burned the sign because it symbolizes a "racist movement."
A police spokesman said Monday that the investigations are still active.
The pro-Trump events this week are expected after Trump last week called for a "wild protest" Wednesday, when a joint session of Congress will announce the official winner of the election.
Mayor Muriel Bowser urged residents Monday to stay away from downtown and not to "engage with demonstrators who come to our city seeking confrontation."