By day, the tombaroli, or tomb raiders, marked out the spot. They used long, pointed tools to pierce the earth, beneath which there was a passage that would take them to Roman homes replete with treasure in Civita Giuliana, a suburb of ancient Pompeii, about 700 metres north-west of the main archaeological park.

By night, they dug a network of tunnels. Each was about 40 metres long, starting from their home or abandoned buildings in the countryside area close to the site, and connected to the passage, from where they hammered through ancient walls as they made their way into the homes to seize their loot.