Dutch police found an “underworld prison” in a warehouse in the city of Bergen op Zoom, according to the news agency AFP.

The prison, built of seven sea containers, hid, among other things, a torture chamber. According to police, the room contained a dentist’s chair and a variety of torture equipment such as pruning shears, a saw, scalpels, hand and finger irons, and masking tape.

- Six of the containers were prisoners, and the sole purpose of one container was to act as a torture chamber, Chief Andy Kraag of the Dutch police tells AFP.

The containers were soundproofed and lined with foil on the inside. Police believe the foil was intended to prevent them from appearing in the thermal camera. All containers had handcuffs installed on the floor and ceiling.

According to police, the abduction of incoming prisoners was carefully planned. The criminals had, among other things, weapons, bulletproof vests and police disguises.

Police arrested six suspects in a warehouse raid. It obtained information about the prison through a Franco-Dutch operation where police hacked into an encrypted EncroChat communications network used by criminals. About 800 people from all over Europe have been arrested during the week during the operation.

Bergen op Zoom is a city of about 66,000 inhabitants in the southern part of the country near the Belgian border.