In Bill O'Reilly and Martin Dugard's new book, they examine the murky circumstances surrounding the death of iconic World War II General George Patton. The official story says that Patton died of injuries suffered in a car accident in Germany in December 1945.

O'Reilly believes the evidence contained in "Killing Patton" points overwhelmingly toward murder.

He explained that Patton had major differences with U.S. policies going forward, strongly believing that the military needed to go after Russia immediately.

"Patton was going to come back to the United States to do a speaking tour. He got in this accident one day before he was scheduled to come back. He was going to tell Americans, Stalin and the Russians are trying to take over the world and that we should harness everything we have, not leave the theater, and go after him," said O'Reilly, adding that Stalin "wanted Patton dead."

The "Factor" host says in his personal opinion, the Russians were behind Patton's death but explains that the book also points to "American duplicity."

O'Reilly believes the country needs a leader like Patton today, saying the "Nazis feared him" and devised their campaigns to avoid his forces.

Watch the interview above, including O'Reilly's plan for a mercenary force to fight ISIS. Check out more on "Killing Patton" at BillOReilly.com.