Rudy Giuliani is under criminal investigation by same office he was once in charge of, and the man who also led that office and served under Giuliani, former SDNY U.S. Attorney David Kelley, tells MSNBC’s Ari Melber that Giuliani’s transformation is ‘pretty incredible’ in an exclusive interview. Kelley notes how Giuliani, now known for his work for Pres. Trump, went from ‘a hard core prosecutor, to a politician,’ and ultimately arrived at his current condition, a subject of a criminal probe – a situation that left Kelley briefly at a loss for words over ‘how to characterize him now.’