Democratic presidential candidate Joe Biden is calling for an investigation of the C.I.A.’s decision to destroy videotapes of interrogations of terror suspects. Biden told a crowd in Waterloo on Monday that he doesn’t trust the Bush Administration to police themselves.

"The C.I.A. was told not to destroy the tapes. They were told allegedly by the White House counsel not to destroy them. They went ahead and destroyed them anyway," Biden said. "That falls in the category of obstruction of justice and/or conspiracy under the criminal code and there’s an investigation required."

According to Biden, an independent prosecutor should be appointed to investigate the case. "Because it may implicate people in the White House or in the justice department or other branches of government, I don’t think that the administration has the credibility to do an in-house investigation," Biden said. "I think the attorney general under the law should appoint a special prosecutor in order to conduct a thorough, independent investigation to find out who is responsible and who is guilty of violating the federal law."

The head of the C.I.A. said last week that his agency taped interrogations of two terror suspects in 2002 and the tapes were destroyed in late 2005. The C.I.A. has said congress was notified of the agency’s intention to destroy the tapes three years before the tapes actually were destroyed, but several key Democrats in congress say that’s not the case.