WILMINGTON, Del. (AP/The Hill) — For more than a year, federal prosecutors have been investigating the Capitol riot, and at least 700 people have been charged, mostly with lower-level crimes.

So it was stunning when prosecutors last week charged the leader of the far-right militia group known as the Oath Keepers, along with 10 other members or associates, with seditious conspiracy, a rarely-used Civil War-era statute reserved for only the most serious of political criminals.

This photo, provided by the Collin County Sheriff’s Office shows Stewart Rhodes. Prosecutors have filed seditious conspiracy charges on Thursday, Jan. 13, 2022, against Rhodes, the leader of the far-right Oath Keepers militia group and 10 suspected associates. The seditious conspiracy case filed this week against members and associates of the far-right Oath Keepers militia group marked the boldest attempt so far by the government to prosecute those who attacked the U.S. Capitol during the Jan. 6 riot. (Collin County Sheriff’s Office via AP)

But court documents show how long in the making it was that Donald Trump’s most fervent and dangerous supporters mobilized to subvert the 2020 election results through force and violence, even though there was no widespread election fraud.

Stewart Rhodes, 56, was arrested Thursday in Little Elm, Texas, and also faces charges for crimes related to the breach of the U.S. Capitol.

The Oath Keepers leader and founder has said he was present at the riot but never entered the Capitol. But members of the group were seen donning paramilitary gear and using a military formation to pass through crowds and enter the Capitol.

“The seditious conspiracy indictment alleges that, following the Nov. 3, 2020, presidential election, Rhodes conspired with his co-defendants and others to oppose by force the execution of the laws governing the transfer of presidential power by Jan. 20, 2021,” Justice Department wrote in a release.

“Beginning in late December 2020, via encrypted and private communications applications, Rhodes and various co-conspirators coordinated and planned to travel to Washington, D.C., on or around Jan. 6, 2021, the date of the certification of the electoral college vote, the indictment alleges. Rhodes and several co-conspirators made plans to bring weapons to the area to support the operation. The co-conspirators then traveled across the country to the Washington, D.C., metropolitan area in early January 2021.”

The indictment released on Thursday contains the first seditious conspiracy charges that have been brought in connection with the riot. The charge carries a maximum possible sentence 20 years in prison for anyone found guilty of conspiring to use force “to prevent, hinder, or delay the execution of any law of the United States.”