Ending a stormy tenure, Ryan left the U.S. attorney's job last month after he was fired in December by his bosses in the Justice Department. Ryan was one of eight U.S. attorneys whose firing has prompted a political firestorm over accusations that the Bush administration axed federal prosecutors for political reasons.

However, Justice Department documents released as part of a congressional inquiry show that Ryan was let go as a result of ongoing concerns about his flawed leadership and sagging morale in the office, even as it investigated some of the most important cases in the country. Those included the Balco steroids probe and the widening investigations of backdating stock options in Silicon Valley.

Career Justice Department official Scott Schools is serving as interim U.S. attorney while California Republicans search for Ryan's replacement. The leading candidates for the job include former San Francisco U.S. attorney Joe Russoniello, former federal prosecutors Dave Anderson, Patrick Robbins and Mike Shepard, and current prosecutors Tim Crudo and Mark Krotoski, according to lawyers familiar with the screening process.