Representative John D. Conyers, the Michigan Democrat who heads the House Judiciary Committee, said he hoped other witnesses would come forward to help lawmakers determine whether Justice Department prosecutors had been “pawns in the game of politics.”

Image Monica Goodling, a former Justice Department official, testified before Congress in May 2007 at the height of the scandal over the firings of nine United States attorneys. Credit... Doug Mills/The New York Times

Ms. Goodling refused to testify until she was given immunity from prosecution — not because she thought she committed any crime, her lawyer has said, but because she feared being vulnerable in the politically charged atmosphere over the firing of the attorneys.

Ms. Goodling said that in the course of her five years at the Justice Department, she interviewed hundreds of job applicants, most of them for positions subject to partisan political appointment. “But some were applicants for certain categories of career positions,” she went on, alluding to workers who are supposed to function free of naked political considerations.

“In every case, I tried to act in good faith, and for the purpose of ensuring that the department was staffed by well-qualified individuals who were supportive of the attorney general’s views, priorities and goals,” she said, before acknowledging that she might have gone too far in asking overtly political questions of some career applicants.

But Representative Bobby Scott, Democrat of Virginia, was not satisfied. “Did you break the law?” he asked. “Is it against the law to take those considerations into account?”

“I believe I crossed the line, but I didn’t mean to,” she replied.

And while she said she had interviewed hundreds of prospective employees, she said it was just not true that, as the White House liaison, she held “the keys to the kingdom.” Nor, she said, did she recall having any conversations with Mr. Rove or with the White House counsel, Harriet Miers, about prospective United States attorneys.

D. Kyle Sampson, former chief of staff to the attorney general, compiled the list of prosecutors to be fired, Ms. Goodling testified. Mr. Sampson testified before the Senate Judiciary Committee in March that Mr. Gonzales himself had been deeply involved in the plans to fire the prosecutors, despite his assertions to the contrary.