Senator Richard Shelby is accusing the Justice Department of abuse in reaction to a published report that federal agents believe he leaked classified messages.
The leaked information was from a meeting the day before 9-11, but The Washington Post reports the leak itself came during June 2002 interviews Shelby did.
The Post, citing anonymous sources, reports Shelby's role was confirmed to FBI agents by Fox News correspondent Carl Cameron, who denies it.
The Post says the interview came after a classified briefing to the Senate Intelligence Committee, where the Alabama Republican was vice chairman.
The information involved two messages the government intercepted the day before Nine-Eleven, saying: "the match begins tomorrow" and "tomorrow is zero day."
Shelby's office calls the story "a grotesque abuse of a public trust on the part of law enforcement."