It was one of the world’s largest and most secure paedophile networks – an online space where tens of thousands traded horror.
The website dealt in abuse; video and images of children, swapped and boasted about on a dark-web forum, accessible only through an encrypted browser.
Membership was tightly managed. Quiet accounts raised suspicion and could be suddenly terminated. Those who stayed had to upload new material frequently. More than 45,000 people complied.
But what those thousands never realised, even as heavy users began to disappear, was that the site was being run by police.