Donald Trump yelling
  • New York prosecutors investigating Trump feared they would have to prove that he was not "legally insane."
  • The revelation is made in an upcoming book by Mark Pomerantz.
  • He said lawyers discussed whether Trump could tell the difference "between bullshit and reality."

New York prosecutors feared they would have to prove that Donald Trump was not "legally insane" as they investigated his business practices, according to an upcoming memoir by a lead attorney on the team.

"To rebut the claim that Trump believed his own 'hype,' we would have to show, and stress, that Donald Trump was not legally insane," lawyer Mark Pomerantz writes in the memoir, seen by The Daily Beast.