The Senate Judiciary Committee's grilling Thursday of Attorney General Alberto Gonzales was rich in human drama but failed to resolve Congress' central questions.

After thousands of pages of documents and hours of testimony from Justice Department officials, it remains unknown who in the Bush administration conceived the plan to fire eight U.S. attorneys and why.

Gonzales' testimony left senators convinced he wasn't behind the plan or its execution and, in fact, knew far less than a department head should have about the details. Former and current members of Gonzales' staff who have been interviewed by congressional investigators also have said their roles were limited or nonexistent.

Absent another explanation, the signs point to the White House and, at least in some degree, to the president's political advisor, Karl Rove.

David Iglesias, the former New Mexico U.S. attorney and one of the eight fired last year, said investigating the White House's role is the logical next step -- one that would follow existing clues about Rove's involvement.

'If I were Congress, I would say, `If the attorney general doesn't have answers, then who would?' There's enough evidence to indicate that Karl Rove was involved up to his eyeballs.''

Iglesias said another clue that the White House may have been the driving force is the relative lack of Justice Department documentation for the firings in the 6,000 pages of documents turned over to Congress.

''If you want to justify getting rid of someone, you should have at least some paper trail,'' Iglesias said. ``There's been a remarkable absence of that. I'm wondering if the paper trail is at the White House.''

Even if Gonzales decides to step down -- he says he won't despite widespread Republican disappointment with his performance -- Democrats say they'll continue their probe into whether politics inappropriately influenced the firings.

''The arrow points more and more to the White House,'' said Sen. Charles Schumer, D-N.Y. ``The one thing I can assure you of: This is not over, far from it.''

That's why some Republicans think Gonzales should stay on the job.

REPUBLICAN SUPPORT

Sen. John Cornyn, R-Texas, told Gonzales in a telephone call Friday that the worst was probably over for him and that stepping down wouldn't necessarily help the president.

In a statement he released later in the day, Cornyn said, 'Democrats see an opportunity to score a lot of political points, so I don't necessarily believe that the attorney general's resignation would quell the Democrats' desire to continue with a partisan fishing expedition.''

Charlie Black, a Republican consultant with ties to the White House, said of Democrats: ``What they're after in this so-called U.S. attorneys investigation is a fishing expedition to try to see if Karl, or somebody else, fired people for political purposes. It would not slow them down if the attorney general left.''

Black added: 'They might decide, `This worked great. Let's go after some other Cabinet official.' ''

Some Republicans, however, want to know more about Rove's role.

Sen. Arlen Specter, R-Pa., immediate past chairman of the judiciary panel, said after Gonzales' testimony, ``Those questions are going to be outstanding to the White House people.

''I believe we will have an opportunity to question them,'' Specter predicted, but he added, ``What the quality of the answers will be remains to be seen.''

Others, however, suggest that they would prefer that Gonzales resign so that the president and his inner circle would be spared from more investigation.

Sen. Tom Coburn, R-Okla., told Gonzales he should resign, but added, ``I disavow aggressively any implication that there was a political nature in this. I know that's the politics of the blood sport that we're playing. I don't think it had anything to do with it.''

Sen. Jeff Sessions, R-Ala., told Gonzales ''you should have said no'' to whoever wanted to fire the attorneys. He said Friday that Gonzales should ''take the weekend'' to reevaluate. ''If he and the president decide that he cannot be an effective leader moving forward, then he should resign,'' Sessions said. But on neither occasion did Sessions go after the White House's role.

Sen. Lindsey Graham, R-S.C., all but told Gonzales he should go during the hearing, but he seemed to dismiss any idea of a cover-up.

''I do believe that your associates have prosecuted both Democrats and Republicans,'' Graham told him. ``I don't believe that you're involved in a conspiracy to fire somebody because they wouldn't prosecute a particular enemy of a politician or a friend of a politician.''

Rep. Adam Putnam, R-Fla., chairman of the House Republican Conference, said Gonzales' tenure is hurting the president's policy agenda, and he's worried that the Democrats are just looking for any reason to get Rove under oath.

BEFORE THE FIRINGS

The investigation shows that complaints about the fired U.S. attorneys came over a two-year period from grass-roots Republicans who were upset with them for various reasons. Most of the complaints were rooted in partisan politics.

Some concerns were ideological, such as whether a prosecutor was doing enough in going after illegal immigration or pornography.

McClatchy Washington correspondent Marisa Taylor contributed to this report.