Theodore L. Gunderson (7 November 1928 – 31 July 2011) was a Federal Bureau of Investigation Special Agent In Charge and head of the Los Angeles FBI, an American author, and a conspiracy theorist. Some of his FBI case work included the Death of Marilyn Monroe and the Assassination of John F. Kennedy. He was the author of the best-selling book "How to Locate Anyone Anywhere Without Leaving Home". In later life he promoted a number of conspiracy theories, notably including satanic ritual abuse.