House Speaker Nancy Pelosi thinks Attorney General William Barr lied to Congress, mischaracterizing special counsel Robert Mueller’s report when he testified in front of a House committee last month. And she thinks that’s a crime.

“What is deadly serious about it is the attorney general of the United States of America was not telling the truth to the Congress of the United States,” Pelosi said at her weekly press conference Thursday. “That’s a crime.”

Pelosi was speaking specifically about Barr’s testimony last month in front of the House Appropriations Committee, during which he said he didn’t know whether Mueller disagreed with his characterization of the special counsel’s report in a four-page summary Barr released in March. We now know Mueller wrote Barr a letter two weeks before his testimony, criticizing the attorney general’s summary. “There is now public confusion about critical aspects of the results of our investigation,” Mueller wrote to Barr.

Standing at the podium on Thursday, Pelosi said Barr’s testimony was so troubling to her that she was unable to sleep the night before.

“He lied to Congress,” Pelosi reiterated in her press conference. “If anybody else did that, it would be considered a crime. Nobody is above the law — not the president of the United States and not the attorney general.”

But when NBC reporter Kasie Hunt asked Pelosi if Barr could be jailed for the offense, the speaker left it up to the committees.

“There’s a process involved here. ... The committee will act upon how we will proceed,” Pelosi said.

.@Kasie: Did AG Barr commit a crime?



Speaker Pelosi: "He lied to Congress. If anybody else did that, it would be considered a crime."@Kasie: Should he go to jail?



Pelosi: "There's a process involved here ... The committee will act upon how we will proceed." pic.twitter.com/kQnfEdL1iD — NBC News (@NBCNews) May 2, 2019

Pelosi’s comments marked a notable escalation of Democrats’ reactions to revelations about how Barr handled Mueller’s report. It’s a signal that Democrats are zeroing in on Barr, rather than President Trump, as their political target. A number of Democrats, including several presidential candidates, called for the attorney general to resign after the news of Mueller’s letter.

Pelosi just went a step further, saying Barr lied to Congress during his testimony and calling those actions criminal. As House speaker, she wields considerable power to determine whether Democrats will pursue impeachment against Trump or others within his administration. So far, she has warned against pursuing impeachment, suggesting the House pursue its oversight investigations instead.

But the Trump administration has been pushing back on those investigations hard — not providing testimony or witnesses, and countersuing Democrats to block their access to certain information. Barr also escalated his conflict with Democrats when he declined to appear for a scheduled hearing before House Judiciary Committee on Thursday, citing objections over letting staff attorneys question him.

Pelosi’s statements are the latest development in a tense week, with the standoff between the White House and congressional Democrats reaching a boiling point. House Judiciary Committee Chair Jerry Nadler (D-NY) has already threatened to hold Barr in contempt of Congress for not showing up to the scheduled hearing on Thursday and not meeting Democrats’ subpoena deadline to produce the unredacted Mueller report.

“The attorney general must make a choice,” Nadler said. “Every one of us must make the same choice. That choice is now an obligation of our office. The choice is simple: We can stand up to this president in defense of the country and the Constitution we love, or we can let the moment pass us by.”