An ethics advocacy group asked the FBI on Wednesday to investigate the White House e-mail controversy, saying electronic messages about the Valerie Plame affair may have been destroyed.

Citizens for Responsibility and Ethics in Washington is basing its request on a White House document describing an effort to recover a week's worth of missing e-mail in 2003 from the office of Vice President Dick Cheney.

The missing e-mail was from a week around the time the Justice Department had begun a criminal investigation into who in the Bush administration leaked Plame's CIA identity to reporters.

White House technicians eventually retrieved e-mail from the missing week, but it is unclear whether all the e-mail from Cheney's office that week has been found.

Cheney's former chief of staff, I. Lewis "Scooter" Libby, was convicted of perjury, obstruction and lying to the FBI in the Plame inquiry.