Sampson, a 37-year-old Cedar City native, was interviewed by Senate staff for nearly six hours Sunday about his role in the decision to dismiss eight U.S. attorneys, and he will be back on Capitol Hill again soon for questioning by House staffers.

In his Sunday meeting, Sampson expanded on his testimony last month before the Senate Judiciary Committee, telling of specific meetings where he discussed the performance of certain prosecutors with Gonzales, according to a congressional source familiar with Sampson's interview.

Sen. Charles Schumer, D-N.Y., also told The Associated Press that Sampson recalled Gonzales telling him last month that President Bush had mentioned concerns about David Iglesias, the U.S. attorney for New Mexico, to the attorney general in October.

Bush has said he recalled a general conversation about complaints with Gonzales from last fall, and Gonzales said March 26 that he did not remember a conversation with the president.

In his written testimony to the committee, Gonzales concedes that some of his past statements were "less than precise," but he insists that "I never sought to deceive the Congress or the American people about my role in this matter."

"In hindsight, I would have handled this differently," Gonzales says in his remarks. He said he should not have delegated so much authority to Sampson, and should have ensured the review was rigorous and that prosecutors were told of the decision "in a more personal and respectful way."

Sen. Orrin Hatch, R-Utah, a member of the Judiciary Committee who has steadfastly defended the embattled Gonzales, said he sees his appearance before the committee as a golden opportunity for the attorney general to present his version of events.

"For weeks, too many people have been speaking for him, most of it pure speculation. Now he'll have the opportunity to provide his perspective on the reasons behind the resignations and the questions that have come up since," Hatch said.

The House Judiciary Committee is scheduled to vote today on whether to take the unusual step of granting immunity in exchange for the testimony of Monica Goodling, who was the liaison between the Justice Department and the White House.

Goodling has asserted her Fifth Amendment right not to testify. It would take a two-thirds vote of the committee to put forward an immunity offer.

Utah Rep. Chris Cannon, the ranking Republican on the subcommittee investigating the prosecutor firings, said the potential offer of immunity is a stunt.

"Given that Ms. Goodling did not request immunity and has not indicated she will do anything other than assert her Fifth Amendment rights against self-incrimination, this immunity offer and the threat of a subpoena are merely meant to fan the flames of speculation and grab headlines," Cannon said.