"The statute did not cause the errors. The FBI's implementation did," the FBI chief told the Senate Judiciary Committee.
But Committee Chairman Sen. Patrick Leahy, D-Vt., served notice: "We're going to be re-examining the broad authorities we granted the FBI in the Patriot Act." House Judiciary committee members delivered a similar message last week.
The Senate panel's ranking Republican, Arlen Specter of Pennsylvania, went further: "The question arises as to whether any director can handle this job and whether the bureau itself can handle the job."
Grim-faced and sometimes even looking pained, Mueller testified at the panel's second hearing into a Justice Department inspector general's report this month that revealed abuses in the FBI's use of documents called national security letters to gather data.
Reviewing headquarters files and four of 56 FBI field offices, Inspector General Glenn Fine found 48 violations of law or presidential directives during 2003-2005. He estimates there may be up to 3,000 unidentified or unreported violations throughout the FBI.
Mueller said he had instituted procedures for issuing these letters. "What I did not do and should have done is put in a compliance program to be sure those procedures were followed," he added.
He is now devising a compliance program and has ordered an audit to determine the extent of the problem and to see if any agents should be disciplined.