On Friday, Trump described Comey as a “Dirty Cop,” claiming: “Whether you like Corrupt James Comey or not, and I can’t imagine too many people liking him, HE LIED! It is not a complex lie, it’s a very simple, but IMPORTANT one.”

Before she was sworn in Monday as an interim U.S. attorney, Halligan, a 36-year-old former White House aide, had no prosecutorial experience.