“This is like any other cover-up,” Mr. Remes said. “We’ve only scratched the surface.”

Plans for the possible prosecution of another prisoner, Ali al-Marri, who has been held since 2003 in a naval brig in Charleston, S.C., could be in jeopardy after the Pentagon recently revealed that it had destroyed some tapes of Mr. Marri’s interrogation. Other tapes showing rough treatment of Mr. Marri, which were discovered in a Pentagon review ordered after the C.I.A. revelations and have been preserved, could prove embarrassing if presented at his trial.

The destruction of tapes has also prompted challenges from lawyers for Zacharias Moussaoui, the convicted Qaeda operative who had unsuccessfully sought testimony at his trial from Abu Zubaydah, one of the two Qaeda suspects whose interrogation videotapes were destroyed in November 2005. At that time, a defense motion seeking records of Abu Zubaydah’s interrogation was pending before a federal court in Virginia.

This motion in the Moussaoui case, among other legal challenges, has raised questions about a statement in December by the C.I.A. director, Gen. Michael V. Hayden, that he understood the tapes were destroyed only after it was determined that they were “not relevant to any internal, legislative, or judicial inquiries.”

A C.I.A. spokesman, Paul Gimigliano, said General Hayden “certainly stands by his statement.” He added: “The C.I.A. has been cooperating with the Department of Justice, the courts and the Congress. The reviews of this matter are not complete, and it is only fair to let them conclude before trying to draw conclusions from them or about them.”

Officially, the C.I.A. has said that the tapes were destroyed primarily because of concerns that their public exposure could endanger the safety of C.I.A. officers. But in interviews in recent months with several officers involved in the decision, they said that a primary factor was the legal risks that officers shown on the tape might face.