WASHINGTON -- Democrats have appealed to Attorney General Alberto Gonzales for more answers about the firings of eight U.S. attorneys, while Republicans have called for the probe to end.

At a hearing Thursday morning with Gonzales as a witness, House Judiciary Chairman John Conyers showed no signs of a willingness to stop asking questions about the firings.

"The department's most precious asset -- its reputation for integrity and independence -- has been called into question," Conyers said. "Until we get to the bottom of how this list was created, and why, those doubts will persist."

The Senate had little luck finding the answers three weeks ago, when Gonzales answered dozens of times that he could not recall key details. He echoed that Thursday, telling the panel that his "feelings and recollections" have not changed.

In the three weeks since his Senate testimony, the department disclosed that it is investigating whether his former White House liaison, Monica Goodling, weighed the political affiliations of those she considered hiring as entry-level prosecutors. Consideration of such affiliations could be a violation of federal law.

Conyers is holding a subpoena for White House political aide Karl Rove for e-mail that may be related to the firings but has not issued it. Meanwhile, the Senate Judiciary Committee last week subpoenaed Gonzales for all e-mails the Justice Department has gathered regarding Rove and the firings.

Conyers pleaded to Gonzales to "cooperate with us," to which the attorney general responded "I'm trying, Mr. Chairman."

Texas Republican Lamar Smith said the probe should end because the number of accusations has grown, while the amount of evidence showing wrongdoing has not.