The Central Intelligence Agency is the American's intelligence agency and MI6's counterpart in the US. The organization appears in Skeleton Key, Ark Angel and Snakehead.
Staff
Joe Byrne is the Deputy Director of the CIA and has had several agants under his command including Tom Turner (deceased), Belinda Troy (deceased), Tamara Knight and Ed Shulsky.
Interactions with Alex Rider
Alex Rider worked for them twice, to bring down General Alexei Sarov (see Skeleton Key) and Nikolei Drevin (see Ark Angel).
Locations
There are two Headquarters shown in books: one is in Miami, the other is in New York. So far, all their undercover locations have used a name to form the anagram "C-I-A."