Cassandra (Who Killed Kennedy)
Unwilling to give his real name, "Cassandra" was a highly placed member of the intelligence community who gave information to James Stevens. He tried to convince Stevens not to investigate UNIT or C19 too deeply.
When Stevens' house was firebombed, Cassandra called to warn him. As a government representative, he officially advised Stevens not to publish Who Killed Kennedy. Unofficially, Cassandra gave him his best wishes. (PROSE: Who Killed Kennedy [+]Loading...["Who Killed Kennedy (novel)"])
Behind the scenes
The character of Cassandra was based on the real world "Deep Throat", a senior intelligence informant who helped Bob Woodward investigate the Watergate scandal. "Deep Throat" was later revealed to have been Mark Felt, however, this was not known at the time Who Killed Kennedy [+]Loading...["Who Killed Kennedy (novel)"] was published. Nonetheless, they are implied to be the same person.