About one-third of the nearly four dozen U.S. attorney's jobs that have changed hands since President Bush began his second term have been filled by the White House and the Justice Department with trusted administration insiders.

The people chosen as chief federal prosecutors on a temporary or permanent basis since early 2005 include 10 senior aides to Attorney General Alberto R. Gonzales, according to an analysis of government records. Several came from the White House or other government agencies. Some lacked experience as prosecutors or had no connection to the districts in which they were sent to work, the records and biographical information show.

The new U.S. attorneys filled vacancies created through natural turnover in addition to the firings of eight prosecutors last year that have prompted a political uproar and congressional investigations.

No other administration in contemporary times has had such a clear pattern of filling chief prosecutors' jobs with its own staff members, said experts on U.S. attorney's offices. Those experts said the emphasis in appointments traditionally has been on local roots and deference to home-state senators, whose support has been crucial to win confirmation of the nominees.

The pattern from Bush's second term suggests that the dismissals were half of a two-pronged approach: While getting rid of prosecutors who did not adhere closely to administration priorities, such as rigorous pursuit of immigration violations and GOP allegations of voter fraud, White House and Justice officials have seeded federal prosecutors' offices with people on whom they can depend to carry out the administration's agenda.

The interim U.S. attorney in Kansas City, Mo., Bradley J. Schlozman, for example, was a deputy in Justice's civil rights division who helped overrule career government lawyers in approving a Texas redistricting plan pushed by Tom DeLay (R-Tex.), then House majority leader. In January, the White House nominated a permanent replacement, John Wood, who is counselor to Deputy Attorney General Paul J. McNulty. Neither Schlozman nor Wood has been a prosecutor before.

Justice officials defend their record of U.S. attorney selections, saying that among Bush's choices since the start of his first term, a larger share have had experience as federal prosecutors than those of President Bill Clinton. One Justice official acknowledged that a number of administration insiders have been chosen but said there was no concerted effort to do so.

As Congress pursues its investigation, some Democrats have indicated they want to explore who has been hired, in addition to the firings that have been the focal point of hearings on Capitol Hill -- and of calls from both parties for Gonzales to resign.

"If we have eight U.S. attorneys dismissed because they were not 'loyal Bushies,' then how many of the remaining U.S. attorneys are?" asked Sen. Richard J. Durbin (D-Ill.), borrowing a phrase that Gonzales's former chief of staff, D. Kyle Sampson, used in an internal e-mail to describe criteria by which prosecutors were chosen to be fired.

"A U.S. attorney's position is a strong line on your résumé. If the administration rewards you with that position and you come straight from Washington, it's hard not to be grateful," Durbin, the majority whip, said in an interview. "That gratitude can translate into loyalty to Washington rather than loyalty to the job."

Choosing insiders as U.S. attorneys is not improper, given the wide latitude the law provides presidents in selecting federal prosecutors, and all administrations tend to choose those who share their basic legal outlook and party affiliation.

Still, academics and other experts say, the appointments appear to alter a long-standing culture of autonomy for the nation's chief prosecutors. James Eisenstein, a Pennsylvania State University political scientist who has written a book on U.S. attorneys, said that historically, federal prosecutors have regarded operating "in a politically neutral, nonpartisan manner" as a cornerstone of their roles. Hiring people from Justice, Eisenstein said, "was very unusual."