After reviewing the accumulating materials, the Commission directed numerous additional requests to Federal and State investigative agencies. The Federal Bureau of Investigation and the Secret Service executed the detailed requests for statements of witnesses and examinations of physical evidence with dispatch and thoroughness. All these reports were reviewed and analyzed by the Commission. Additional investigative requests, where appropriate, were handled by Internal Revenue Service, Department of State, and the military intelligence agencies with comparable skill. Investigative analyses of particular significance and sensitivity in the foreign areas were contributed by the Central Intelligence Agency. On occasion the Commission used independent experts from State and city governments to supplement or verify information. During the investigation the Commission on several occasions visited the scene of the assassination and other places in the Dallas area pertinent to the inquiry. The scope and detail of the investigative effort by the Federal and State agencies are suggested in part by statistics from the Federal Bureau of Investigation and the Secret Service. Immediately after the assassination more than 80 additional FBI personnel were transferred to the Dallas office on a temporary basis to assist in the investigation. Beginning November 22, 1963, the Federal Bureau of Investigation conducted approximately 25,000 interviews and reinterviews of persons having information of possible relevance to the investigation and by September 11, 1964, submitted over 2,300 reports totaling approximately 25,400 pages to the Commission. During the same period the Secret Service conducted approximately 1,550 interviews and submitted 800 reports totaling some 4,600 pages.