D.C. Attorney General Karl A. Racine (D) on Tuesday sued the Proud Boys and Oath Keepers over the Jan. 6 attack on Congress, seeking to use a law written to cripple the Ku Klux Klan to seek stiff financial penalties from the far-right groups that Racine alleges were responsible for the violence.

The lawsuit filed in federal court in Washington cites the modern version of an 1871 law known as the Ku Klux Klan Act, which was enacted after the Civil War to safeguard government officials carrying out their duties and protect civil rights. Two similar suits have been filed already this year related to Jan. 6 — one by Rep. Bennie G. Thompson (D-Miss.), chair of the House Homeland Security Committee, and another by a number of police officers who fought the rioters that day.

Racine’s suit, however, is the first effort by a government agency to hold individuals and organizations civilly responsible for the violence at the U.S. Capitol on the day Congress ceremonially confirmed President Biden’s 2020 election victory.