Mass Effect & Mass Effect 2
Citadel Security is a volunteer police service answering to the Citadel Council. The 200,000 constables of C-Sec are responsible for maintaining public order in the densely populated Citadel. They also provide pirate suppression, customs enforcement, and search-and-rescue throughout the Citadel cluster.
C-Sec has six divisions:
ENFORCEMENT - Uniformed officers who patrol the Citadel and respond to emergencies.
INVESTIGATION - Detectives who puzzle out the truth behind crimes and bring perpetrators to justice.
CUSTOMS - Screens the thousands of passengers and cargo containers that pass through the Citadel's ports every day.
NETWORK - Deals with "cybercrimes" like identity and copyright theft, hacking and viral attacks, and illegal artificial intelligence.
SPECIAL RESPONSE - Deals with hostage situations, bombs and heavily armed criminals. In the unlikely event that attackers board the Citadel, they are also the front line of defense, armed with military grade equipment.
PATROL - Naval arm, with ships stationed throughout the Citadel cluster. Unlike the other divisions, they are rarely seen at the Citadel, nor do they stay in once place long.
Joining C-Sec is prestigious; applications must be sponsored by a Citadel Councilor or the ambassador of an associate Council race. Generally, applicants have many years of distinguished service in the military or police forces of their nation, but an inexperienced applicant with demonstrable talent will be considered.
C-Sec and the Spectres are often at odds. Many C-Sec members, notably current Executor Venari Pallin, believe that allowing Spectres to be 'above the law' is a dangerous practice; the actions of Saren Arterius lend credence to this position. The Spectres, in turn, are aggravated when C-Sec's dedication to procedure and due process hampers their investigations.