The NAACP filed a lawsuit Tuesday against former President Trump and far-right extremist groups in connection with the Jan. 6 Capitol riots that killed five people and injured dozens of officers.

Why it matters: The federal lawsuit filed on behalf of House Homeland Security Chairman Bennie Thompson (D-Miss.) shows that Trump continues to face legal problems stemming from the riot, even after he was acquitted in his Senate impeachment trial Saturday.

Details: The lawsuit — filed in the U.S. District Court in Washington, D.C., by the NAACP and civil rights law firm Cohen Milstein Sellers & Toll — accuses Trump, his attorney Rudy Giuliani, the Proud Boys, and the Oath Keepers of conspiring to incite a riot at the Capitol with the goal of preventing Congress from certifying the 2020 presidential election.

• The lawsuit alleges that Trump, Giuliani and the far-right groups directly violated the 1871 Ku Klux Klan Act by trying to prevent Congress from carrying out its official duties.
• The insurrection forced members of Congress to hide under desks and in secure rooms as rioters damaged the building and shouted violent threats.
• The NAACP said U.S. Reps. Hank Johnson (D-Ga.) and Bonnie Watson Coleman (D-N.J.) intend to join the lawsuit as plaintiffs in the coming weeks. 

The 1871 Ku Klux Klan Act allowed President Ulysses S. Grant to declare martial law, impose heavy penalties against terrorist organizations, and use military force to suppress the Ku Klux Klan after the Civil War.

• Former Confederate soldiers had organized under the Ku Klux Klan to terrorize newly emancipated enslaved African Americans and stop them from gaining political power.
• The law was aimed at protecting against conspiracies. 

What they're saying: "The insurrection and coup attempt was really motivated by white supremacist behavior and domestic terrorists. The NAACP thinks it's important for us to pursue a course of action on behalf of members of Congress," NAACP president Derrick Johnson told Axios.

• "The attempt was to prevent the certification of the election and invalidate African American votes."
• "We must hold (Trump) accountable for the insurrection that he so blatantly planned. Failure to do so will only invite this type of authoritarianism for the anti-democratic forces on the far right that are so intent on destroying our country," Thompson said in a statement.

Don't forget: Some of the insurrection participants waved Confederate flags, wore racist and anti-Semitic clothing, and called for then-Vice President Mike Pence to be lynched.

The other side: "President Trump has been acquitted in the Democrats' latest impeachment witch hunt, and the facts are irrefutable. President Trump did not plan, produce or organize the Jan. 6th rally on the Ellipse. President Trump did not incite or conspire to incite any violence at the Capitol on Jan. 6th," Trump adviser Jason Miller said in a statement.

Between the lines: In addition to lawsuits, Trump could face criminal charges in Georgia.

• Prosecutors there have launched an investigation into Trump's efforts to overturn the state's 2020 election results, including a phone call with the state's top elections official in which the former president asked to "find" enough votes to declare he won Georgia.