WASHINGTON — All but one of the U.S. attorneys recently fired by the Justice Department had positive job reviews before they were dismissed, but many ran into political trouble with Washington over issues ranging from immigration to the death penalty, according to prosecutors, congressional aides and others familiar with the cases.

Two months after the firings first began to make waves on Capitol Hill, it has also become clear that most of the prosecutors were overseeing significant public-corruption investigations at the time they were asked to leave. Four of the probes target Republican politicians or their supporters, prosecutors and other officials said.

The emerging details stand in contrast to repeated statements from the Justice Department that six of the Republican-appointed prosecutors were dismissed because of poor performance. In one of the most prominent examples, agency officials pointed to widely known management and morale problems surrounding then-U.S. Attorney Kevin Ryan in San Francisco.

But the assertions enraged the rest of the group, some of whom feel betrayed after staying silent about the way they had been shoved from office.

Bud Cummins, the U.S. attorney in Little Rock, Ark., who was asked to resign earlier than the others to make way for a former White House aide, said Justice Department officials crossed a line by publicly criticizing the performance of his well-regarded colleagues.

"They're entitled to make these changes for any reason or no reason or even for an idiotic reason," Cummins said. "But if they are trying to suggest that people have inferior performance to hide whatever their true agenda is, that is wrong. They should retract those statements."

Justice Department officials initially sought to obscure the firings even from some senators and have since issued confusing signals and contradictory information about the episode.

One source who was familiar with the episode said last week that an eighth U.S. attorney was asked to resign along in December with the others. The unidentified prosecutor is negotiating to stay in the job, said the source, who spoke on the condition of anonymity because of the delicacy of those discussions.

The end result is an unusual spectacle in which Democratic lawmakers are bemoaning the firings of Republican-appointed prosecutors. The political pressure has become so great that Cummins' successor in Arkansas, former White House aide Timothy Griffin, announced Friday that he had decided not to submit his name to the Senate for a permanent appointment.