The FBI frequently investigated Martin Luther King, Jr. In the mid-1960s, King began publicly criticizing the Bureau for giving insufficient attention to the use of terrorism by white supremacists. Hoover responded by publicly calling King the most "notorious liar" in the United States.  In his 1991 memoir, Washington Post journalist Carl Rowan asserted that the FBI had sent at least one anonymous letter to King encouraging him to commit suicide.  Historian Taylor Branch documents an anonymous November 1964 " suicide package " sent by the Bureau that combined a letter to the civil rights leader telling him, "You are done. There is only one way out for you..." with audio recordings of King's sexual indiscretions. 
"The FBI has created an email for parents and guardians who have reason to believe their child/children may be a victim in this investigation. Please email BayAreaTips@ and include your full name, phone number, your child’s full name and age, why you believe your child may be a victim, the date range which your child may have been in contact with the subject and the venues where your child may have been in contact with the subject. This email address has specifically been set up for this investigation. You may be contacted by an Agent to gather further information. Your patience is appreciated at this time."