Mr. Kohl pointed as well to findings by an inspector general investigation to say that the two agents who interviewed Mr. Flynn at the White House in January 2017 — Peter Strzok and Joe Pientka, who would be key witnesses in any trial — were tainted. Mr. Strzok had sent text messages to a colleague indicating that he did not like Mr. Trump; Mr. Pientka helped supervise error-riddled applications to wiretap a different former Trump campaign adviser who was under investigation as part of the F.B.I.’s Russia investigation, Carter Page.
“The I.G. knocked out all of our witnesses in this case,” Mr. Kohl said.
Mr. Gleeson, however, scoffed. He pointed out that the Justice Department did not need to prove Mr. Flynn’s statements because he had already pleaded guilty. He also said that the department would argue in any other case that bias by agents or violations of internal rules were irrelevant, and maintained that it would be easy to prove Mr. Flynn lied.
On Twitter, Mr. Strzok accused Mr. Kohl of “materially misrepresenting” his actions.
Separately, in a letter docketed on Monday night, a lawyer for Mr. Strzok told Judge Sullivan that someone had altered handwritten notes by his client in one of the recent batches of internal materials turned over to Ms. Powell — adding two dates to them that he did not write, including one that suggested a White House meeting happened earlier than it did.
Judge Sullivan ordered the Justice Department to provide a sworn declaration certifying whether the materials submitted to him “were true and accurate,” saying he was “floored” by the “unsettling” claim that they had been modified.
Ms. Powell sparred with Judge Sullivan, initially resisting his demand that she tell him whether she had spoken with Mr. Trump about the case on the grounds that it was subject to executive privilege.
After he pointed out that she did not work for the government, and so the privilege did not apply to her, she said she had recently briefed Mr. Trump about developments in the case and asked him not to pardon her client. Pressed further, she cited The New York Times as reporting that she had spoken to Mr. Trump at least five times.
As she has many times before, Ms. Powell also portrayed the case against her client as a corrupt and politically motivated conspiracy and demanded that Judge Sullivan recuse himself. He told her to file a written motion for recusal if she wanted.