The ZEP is the secret police of the nation of Borduria. They engage in sabotage espionage. Their agents are first seen in King Ottokar's Sceptre, attempting a coup d'etat in their rival neighbouring nation of Syldavia. They then re-appear in The Calculus Affair as the culprits behind Professor Calculus' kidnapping. They work in close relation with the government of San Theodoros while under General Tapioca's rule as seen in Tintin and the Picaros.