Paul Le Roux ran an international online prescription drug network, selling hundreds of millions of dollars worth of painkillers to Americans. He ordered the murders of least six people. He orchestrated massive shipments of North Korean meth and Columbian cocaine. He helped sell weapons to the Iranian government and Somali militias. U.S. law enforcement spent more than a decade trying to bring him down. That story is told in a new book called “The Mastermind.”