In a January 2005 letter to Congress, then-Assistant Defense Secretary Paul Wolfowitz admitted the Defense Department "did conduct business with companies that, in turn, subcontracted work to second-tier providers who leased aircraft owned by companies associated with Mr.But that didn't stop U.S. government contractors from paying Bout-controlled firms roughly $60 million to fly supplies into Iraq in support of the U.S. war effort, according to a book released last year by two reporters who investigated Bout."Even with all power of American administration, CIA, FBI and all means like satellites and this, they not even able to come back with a certain proof so that I could answer," he said in choppy English.A Defense Department spokesman confirmed to the authors that Bout's fleet were provided nearly 500,000 gallons of fuel from the Baghdad airport courtesy of the U.S. Air Force.Using a "veiled, complex corporate structure," Bout dispatched fleets of Cold War-era Soviet cargo planes to some of the most inhospitable corners of the earth, running guns for dictators, including Liberia's Charles Taylor and Zaire's Mubuto Sese Seko, as well as rebel leaders in Angola, Sierra Leone and beyond."