An intelligence officer is a person employed by an organization to collect, compile and analyze information (known as intelligence) which is of use to that organization. Organizations which employ intelligence officers include armed forces, police, civilian intelligence agencies and customs agencies.
The actual role carried out by an intelligence officer varies depending on the remit of his/her parent organization. Officers of foreign intelligence agencies (e.g. the United States' Central Intelligence Agency or the United Kingdom's Secret Intelligence Service (MI6)) may spend much of their careers abroad. Officers of domestic intelligence agencies (such as the United States' Federal Bureau of Investigation or the UK's Security Service (MI5) are responsible for counter-terrorism, counter-espionage, counter-proliferation and the detection and prevention of serious organized crime within their own countries (although, in Britain, the Serious Organized Crime Agency has been set up to take care of serious organized crime).
Responsibilities which are common to most intelligence officers include compiling and analyzing intelligence to determine the identities, intentions, capabilities and activities of hostile individuals or groups, and planning or enacting the necessary steps to disrupt or prevent such activities.