Mr. X

First Line: "You have a friend in the FBI."
Last Word: Writes "SRSG" in his blood on Fox's floor to lead him to Maurita Covarrubias
Position: works for CSM and Syndicate
Death: 1996; Killed by a Syndicate assassin after the First Elder sets a trap to discover the source of Mulder's information
Informant: Helps Mulder; Refuses to risk his life for Mulder