The FBI began COINTELPRO in 1956 against the Communist Party and expanded it to other groups. In 1967 it launched a program against what it called Black nationalist hate groups, and a 1968 memo set the goal of preventing the rise of a Black "messiah." Agents used informants, forged letters, wiretaps and planted stories to discredit activists and turn groups against each other. In 1964, the FBI sent King an anonymous letter that urged him to kill himself. It also targeted the American Indian Movement, Puerto Rican independence groups and anti-war activists.
The program became public after activists broke into an FBI field office in Media, Pennsylvania, in March 1971 and gave stolen files to reporters. The Senate's Church Committee investigated in 1975 and 1976 and found the FBI had broken the law.
COINTELPRO is the reason many organizers distrust government surveillance. Civil liberties groups compare it to modern monitoring of protest movements, including Black Lives Matter.