Massacre at Jamestown

Remember Jim Jones and the poisoned Kool-Aid? Here's the conspiracy theory in a nutshell: a socalist cult is slaughtered by the CIA and covered up as mass suicide. Immediately preceding this, an anti-CIA congressman from California is shot dead by some assassins. Read the wiki entry for the conspiracy. And read the wiki entry for the conventional story.

Here's someone who was a part of the Temple, going into more detail on the links to the CIA. Hello CIA.
Another article about the local pathologists findings, and all of the conflicting reports about the number of dead, the presence american and british commandos, etc (these are all taken off of that first wiki link).