Andrew C. McCarthy served as Chief Assistant U.S. Attorney for the Southern District of New York. He led the successful prosecution of the "Blind Sheikh," Omar Abdel Rahman, and his accomplices in connection with the 1993 World Trade Center bombing and other plots to attack New York City landmarks.

Now a contributing editor and columnist with National Review, McCarthy has tracked every step of of the Trump-Russia investigations. His new book is "Ball of Collusion: The Plot to Rig an Election and Destroy a Presidency."

In the first part of our conversation, McCarthy explained to Greg Corombos how the investigation really started, the role of then-CIA Director John Brennan, and how President Obama must have known and quite likely approved the investigation.

In the book, McCarthy says there is no evidence whatsoever of conspiracy between the Trump campaign and the Kremlin. If that's true, then why did the Mueller investigation take almost two years to complete?

"When you look at the indictments Mueller filed, it's quite clear not only that there wasn't a Trump-Russia conspiracy but that they affirmatively knew there wasn't a Trump-Russia conspiracy," said McCarthy.

Listen to the full podcast as McCarthy also offers a compelling case that Mueller and his team knew there was no conspiracy more than 18 months before releasing their report earlier this year.