U.S. President Barack Obama will announce Friday his new choice to lead the Federal Bureau of Investigation (FBI) in Jim Comey, former President George W. Bush's number two at the Justice Department, the White House said Thursday. If confirmed by the Senate, Comey would replace Robert Mueller. Mueller will resign September 4 after overseeing the bureau's transformation into one the country's chief weapons against terrorism. Comey was a federal prosecutor who went on to serve as deputy attorney general under Bush. In recent years, he has worked as a head fund executive and lectured at Columbia Law School.