"This is political," Iglesias recalls Texas U.S. Attorney Johnny Sutton telling him shortly after he was ousted. "If I were you, I'd just go quietly."

Iglesias, a former U.S. attorney in New Mexico, is one of nine federal prosecutors whose firings triggered a yearlong controversy at the Justice Department and led to the resignations of Attorney General Alberto Gonzales and 11 other Justice Department officials.

Iglesias cites the exchange with Sutton in his upcoming book, "In Justice," as further evidence that he was forced out because Republicans were displeased with his refusal to prosecute Democrats.

"I couldn't believe what I was hearing: a U.S. attorney all but admitting that a colleague was being hung out to dry for reasons that had nothing to do with performance or professionalism," he wrote in a draft of the book, which McClatchy obtained.