On November 18, 1978, over 900 members of a religious group led by the Reverend Jim Jones were killed in an apparent mass suicide. The megalomaniac Jones convinced most of his followers to drink a cyanide mixture. Some, including Jones, were shot, either in suicide or murder.
Shortly before the mass suicide, U.S. Congressman Leo Ryan was assassinated on Jones' orders. Ryan had just landed in Guyana to investigate alleged human rights abuses at Jonestown.
Jim Jones, born May 13, 1931 in Lynn, Indiana, had his own religious congregation, the People's Temple Full Gospel Church, in Indianapolis by 1963. Jones led the interracial congregation (rare at the time) with faith healing, visions and advice from extraterrestrials.
After spending a short time in Brazil, Jones moved his congregation to California. He eventually moved it again to an isolated area of Guyana jungle, naming the new settlement after himself.
Rumors abound of government connections to the Guyana tragedy.
A former Jones cult member, Phil Kerns, wrote a book claiming that "Jones was a Marxist who had numerous contacts with officials of both the Cuban and Soviet governments."
Others claim the CIA was involved in Jonestown, possibly as part of a mind control experiment. The CIA definitely had operations in socialist Guyana, and was certainly interested in cult members' Soviet embassy visits. The CIA did have a mind control program, MK-ULTRA, the famous "LSD in your coffee" experiments. One of Leo Ryan's congressional aides, among others, suspects that the CIA did not disband the program in 1973, as it claims, but instead continued the effort in religious cults like Jonestown.
In 1980, the House Permanent Select Committee on Intelligence reported "no evidence" of CIA involvement in Jonestown.
Source: Excerpt from Johnathan Vankin and John Whalen's 50 Greatest Conspiracies of All Time, posted by Charles Zeps to the Libernet mailing list on August 7, 1995.