WASHINGTON — D. Kyle Sampson has agreed to voluntarily testify before the Senate Judiciary Committee next week, according to a letter sent to committee leadership by his attorney Bradford Berenson late Friday.

Sampson, a Utah native and former chief of staff to Attorney General Alberto Gonzales, resigned from his job March 12 in connection with the firing of eight U.S. attorneys, now under investigation by Congress.

"Mr. Sampson looks forward to answering the committee's questions," Berenson said. "We trust that his decision to do so will satisfy the need of the Congress to obtain information from him concerning the requested resignations of the United States attorneys."

Berenson had requested an extension until at least April 2 to accommodate a family vacation as well as to give Sampson time to prepare for his appearance, but a Senate committee staff member called Berenson on Friday refusing the postponement request.

The House and Senate Judiciary Committee chairmen have each been authorized by committee members to issue subpoenas to Sampson and White House Deputy Chief of Staff Karl Rove — also a former Utahn; former White House counsel Harriet Miers; and other White House and Justice Department officials. Gonzales is also expected to testify before Congress, although a date for that has not been set.

Senate Judiciary Chairman Patrick Leahy, D-Vt., welcomed Sampson's decision.

"We invite and hope for cooperation in our investigation, and subpoenas will be used only if needed," Leahy said in a statement. "Mr. Sampson is a key figure in this matter, having played an integral role in the planning and execution of the firings and replacements of these prosecutors, along with White House political advisers."

Meanwhile, Senate Majority Leader Harry Reid, D-Nev., said he believes Gonzales likely will be gone in a month, "one way or the other."

Bloomberg News reported that Reid also believes a compromise will be reached with the Bush administration over testimony of White House officials in the firing probe that would allow some officials to testify in private without sworn testimony, as long as the deal doesn't involve Bush's top political adviser, Karl Rove.

"Certainly, Karl Rove, with his resume, would have to be under oath," Reid said in an interview with Bloomberg TV's "Political Capital with Al Hunt," scheduled to air this weekend. "He simply in my opinion, and I think the majority of the American people, is not trustworthy."