WASHINGTON — The Justice Department opened a criminal investigation into the destruction of CIA interrogation videotapes and Attorney General Michael B. Mukasey appointed an outside prosecutor to oversee the case.

The CIA acknowledged last month that it destroyed videos of officers using tough interrogation methods while questioning two al-Qaida suspects. The acknowledgment sparked a congressional inquiry and a preliminary investigation by Justice.

"The Department's National Security Division has recommended, and I have concluded, that there is a basis for initiating a criminal investigation of this matter, and I have taken steps to begin that investigation," Mukasey said in a statement released Wednesday.

Mukasey named John Durham, a federal prosecutor in Connecticut, to oversee the case. Durham has a reputation as one of the nation's most relentless prosecutors. He served as an outside prosecutor overseeing an investigation into the FBI's use of mob informants in Boston and helped send several Connecticut public officials to prison.

"The CIA will of course cooperate fully with this investigation as it has with the others into this matter," agency spokesman Mark Mansfield said.

The CIA has already agreed to open its files to congressional investigators, who have begun reviewing documents at the agency's Virginia headquarters. The House Intelligence Committee has ordered Jose Rodriguez, the former CIA official who directed the tapes be destroyed, to appear at a hearing Jan. 16.

Rodriguez's attorney, Robert S. Bennett, had no comment.