Six men have been arrested in the Netherlands following the discovery of seven shipping containers converted into cells and torture chambers.
The containers were located in Wouwse Plantage, south of Rotterdam, after French police cracked encrypted phones used by criminals.
Dutch police said the containers were found before they were used, and potential victims were now in hiding.
Police found another warehouse, thought to be a base in Rotterdam.
The suspects were arrested on 22 June following a Franco-Dutch operation to infiltrate the EncroChat encrypted phone system.
Police intercepted millions of messages including that of one of the suspects, a 40-year-old man from The Hague. Investigators were able to access his contacts via an Encrochat phone.
Those messages allegedly included images of a shipping container with a dental chair that had straps on the armrests and footrest.
After locating the containers in April in Wouwse Plantage, near the Belgian border, police put the area under observation and found that multiple men were working on them almost every day. When the containers were almost finished, investigators decided to intervene.
A video posted online by police shows officers arresting the suspects and also entering the containers.
Officers found handcuffs attached to the floors and ceilings of the containers, which had also been soundproofed.
In one container, they also discovered police clothing and bulletproof vests. In another, they located pruning shears, scalpels and balaclavas.
The arrests are among 800 made across Europe after EncroChat messages were intercepted and decoded.