Crypteia

The Crypteia, also referred to as Krypteia or Krupteia (Greek: κρυπτεία krupteía from κρυπτός kruptós, "hidden, secret"; members were κρύπται kryptai), was an ancient Spartan state institution. The kryptai either principally sought out and killed helots across Laconia and Messenia as part of a policy of terrorising and intimidating the enslaved population; practiced a form of military training; endured hardships as an initiation ordeal; or served a combination of all these purposes, possibly varying over time. Whatever its true nature, the Crypteia was an element of the Spartan state's child-rearing system for upper-class males.

Modern historians often translate "Krypteia" as "secret police" or "secret service", but its precise structure is debated.