The Center for State Security (or CSS) was a secretive Terran Confederacy organization.
Senator Canon tried to unearth its secrets. In 2496, in order to keep their secrets, Center employee Leonid Celsus dispatched a ghost to assassinate Canon, framing his bodyguard Nuura Joss for the deed.
Joss survived and pleaded guilty to the crime. A somewhat surprised Celsus planned to later manipulate her in prison.
In early 2499, Tamsen Cauley was ordered to attend to a "sensitive" matter. A battlecruiser, the Hephaestus, had been carrying zerg organisms, but the creatures had gotten out. The crew had called for help, but Cauley was ordered to send a "maximum deniable" team to take care of the matter. Cauley ordered the War Pigs, a band of disposable outlaw soldiers, to meet him there. He ordered them to destroy the Hephaestus.