The Central Intelligence Agency (CIA) is a civilian foreign intelligence service of the federal government of the United States, tasked with gathering, processing, and analyzing national security information from around the world, primarily through the use of human intelligence (HUMINT). As one of the principal members of the United States Intelligence Community (IC), the CIA reports to the Director of National Intelligence and is primarily focused on providing intelligence for the President and Cabinet of the United States.
Plot relevance[]
The CIA is relevant to the plot of Sherlock series two episode "A Scandal in Belgravia, where the CIA and its agents act as obstacles to Sherlock Holmes investigation into Irene Adler and the compromising images of a young female member of the British Royal family that she took during a dominatrix session.
The CIA, and most notably their agent Neilson, are working with Mycroft Holmes and the British government on trying to protect their "Bond Air" plan which was compromised when Irene Adler seduced a member of the M.O.D and stole evidence of the plan.
There agents first appears when they arrive at Adler's house at the same time that Sherlock and John are there investigating Adler. They want access to Adler's safe's they can recover the stolen information but can't rely on Adler as they know that there is a second passcode that burns the content of the safe. They know of Sherlock's reputation and skill, possibly from Mycroft, and order him to open the safe as they had been listening in and heard Adler say that she had already told Sherlock the passcode.
A slightly confused Sherlock insists that the doesn't know the code but, when John is threaten he guesses that the code is Irene's measurements and opens the safe. Sensing that the safe is booby trapped he uses the "vatican cameos" safe word to tell John to duck. The safe open and a gun inside fires hitting a CIA agent, Sherlock, John and Irene take the moment of surprise and attack the remaining CIA agents.