Speaker Nancy Pelosi (D-Calif.) said in a letter to House Democrats Monday an independent "9/11-type Commission" will be set up to investigate the Jan. 6 U.S. Capitol insurrection.

Why it matters: Calls for a bipartisan commission to investigate the deadly attack have grown in recent weeks, and escalated since former President Trump was acquitted Saturday of charges of high crimes and misdemeanors.

• This could be the last avenue for some lawmakers to hold Trump to account for the siege.
• Republicans who support an independent inquiry include Sen. Lindsey Graham (R-S.C.), a key ally of the former president who voted to acquit him.

What she's saying: "To protect our security, our security, our security, our next step will be to establish an outside, independent 9/11-type Commission to 'investigate and report on the facts and causes relating to the ... domestic terrorist attack upon the United States Capitol Complex," Pelosi said in her letter.

• "And relating to the interference with the peaceful transfer of power, including facts and causes relating to the preparedness and response of the United States Capitol Police and other Federal, State, and local law enforcement in the National Capitol Region."

For the record: Pelosi last month appointed Lt. General Russel Honoré to conduct a security infrastructure review of the Capitol following the riots.

• After consulting with Honoré, Pelosi wrote Monday that she would move forward with plans for emergency funding laws "to provide for the safety of members and the security of the Capitol."

Of note: Reps. Jim Jordan (R-Ohio), James Comer (R-Ky.), Devin Nunes (R-Calif.) and Rodney Davis (R-Ill.) wrote to Pelosi on Monday to express concerns about the independence of Honoré and his final recommendations, and whether the Speaker would have an influence on the outcome.

What to watch: Legislation would probably be needed to establish a commission, like the one created following the Sept. 11, 2001 attacks, which saw then-President George W. Bush signed a law giving the panel investigation powers, the New York Times notes.