In the late 1990s he was assigned as a special attorney in Boston leading an inquiry into allegations that F.B.I. agents and police officers had been compromised by mobsters.

In taking over the inquiry, Mr. Durham is expected to be able to move ahead without a long delay because his team will include Justice Department prosecutors who have already been working on the case. But at least in the beginning, it is likely to proceed more slowly than parallel investigations on Capitol Hill that are already well under way. Investigators from the House Intelligence Committee last month reviewed C.I.A. documents related to the destruction of the tapes, and the committee has called government witnesses to testify at a hearing scheduled for Jan. 16.

Mr. Mukasey pointedly did not designate Mr. Durham as a special counsel, in effect refusing to bow to pressure from Congressional Democrats to appoint an independent prosecutor with the same broad legal powers that were given to Patrick J. Fitzgerald, the special counsel who was appointed in 2003 to lead the investigation into the disclosure of a C.I.A. officer’s identity. That inquiry resulted in the perjury and obstruction prosecution of I. Lewis Libby Jr., formerly Mr. Cheney’s chief of staff. After Mr. Libby’s conviction, President Bush commuted his sentence.

Mr. Fitzgerald was appointed after the attorney general at the time, John Ashcroft, determined that his own relationship with officials under possible scrutiny in the leak case forced him to recuse himself from the investigation. As special counsel, Mr. Fitzgerald had the authority of the attorney general for the matters under investigation.

Mr. Durham will report to the deputy attorney general, an office being held temporarily by Craig S. Morford. Mr. Durham will have the powers of the United States attorney for the Eastern District of Virginia, a jurisdiction that includes C.I.A. headquarters. If a grand jury is convened as expected, it will meet in Alexandria, Va., where the prosecutor’s office is located.

Mr. Mukasey said “in an abundance of caution” the office of United States attorney for the district, Chuck Rosenberg, had been recused from the case and would not take part in the inquiry. Mr. Rosenberg’s office has investigated cases of detainee abuse by C.I.A. employees and contractors and has worked closely with the C.I.A. on counterterrorism and espionage cases.

Mr. Mukasey said the decision was made “to avoid any possible appearance of a conflict with other matters handled by that office.” Appointments like Mr. Durham’s are sometimes made in cases in which prosecutors like Mr. Rosenberg have recused themselves.