Three unidentified individuals raided a Credit Agricole bank branch in Naples on April 16, first digging a 12-meter underground tunnel to gain entry and escape, RIA Novosti reports.

According to geologist Gianluca Minin, who prepared a 3D design for the tunnel for the Carabinieri, its construction took several weeks. The tunnel, approximately 80 centimeters in diameter, was dug by hand—presumably with entrenching shovels and rakes—to avoid attracting attention. The tunnel led into the city's underground utility system; the sewer manholes located near the bank had been welded shut beforehand.

The robbers entered the branch wearing work clothes, caps, and masks, then blocked the emergency exit and took 25 people—bank customers and employees—hostage. About an hour later, the robbers escaped through an underground passage.

According to the newspaper Repubblica, the criminals stole the contents of 40 safe-deposit boxes. Investigators are not ruling out the possibility that the robbers acted on a tip: they only broke into the boxes belonging to clients of the now-closed bank branch, which were known for their weak security. Affected clients note that such boxes "can be opened with a regular screwdriver."