(CNN) House Judiciary Chairman Jerry Nadler threatened to depose acting Attorney General Matthew Whitaker in a letter Wednesday, calling his testimony "unsatisfactory" or "contradicted by other evidence."

The New York Democrat, in his letter released Wednesday evening, told CNN earlier Wednesday that Whitaker "may have" misled the committee in testimony last week.

"Although the committee appreciates your decision to appear, members on both sides of the aisle found many of your answers to be unsatisfactory, incomplete or contradicted by other evidence," Nadler's letter read. "You repeatedly refused to offer clear responses regarding your communications with the White House, and you were inconsistent in your application of the Department's policy related to the discussion of ongoing investigations."

The letter from Nadler continues the back and forth between House Democrats and Whitaker, whom President Donald Trump tapped to lead the Justice Department on an interim basis after he fired Attorney General Jeff Sessions. The fiery hearing last Friday followed a public spat over Whitaker's appearance and the threat of a subpoena from Nadler to compel testimony.

In Wednesday's letter, Nadler cited exchanges from the hearing with which he was unsatisfied, including moments when members of Congress asked Whitaker about reported conversations he had with Trump regarding the President's former attorney Michael Cohen.