听力原文： The report by the Justice Department's inspector general says the FBI improperly and at times illegally abused its power when it demanded and received customer information from telephone companies, Internet service providers and financial institutions in the course of terrorism and espionage investigations. The report found that the FBI misused the authority contained in what are called National Security Letters to compel the release of private information without getting prior approval from a judge or a grand jury. The use of the letters as an investigative tool has expanded dramatically' since the 2001 terrorist attacks on the United States. The inspector general's report found 26 possible violations by the FBI and said 22 of those would result from errors by the bureau. Already two House Committees have announced they will hold hearings on the FBI violations. Which is NOT one of the sources from which FBI could get customer information?