Introduction
During a large-scale CSAM operation involving multiple suspects across a UK region, investigators received a hard drive labelled as having been ‘cleared’ by thumbnail review. The device had over 300,000 image and video files, the majority of which had been previously classified as adult content.
The reviewing officer, however, noticed a set of folders containing nearly identical stills from bedroom webcams. These images, taken at night, showed little more than a dimly lit room and an empty bed. Each image was taken seconds apart, but none appeared suspicious when viewed individually.
Concerned that something was being missed due to subtle visual changes, the team re-analysed the material using S21 VisionX.
S21 VisionX didn’t show us a single image. It showed us a sequence. That’s what changed everything.
The full set of webcam captures was processed in S21 VisionX, where we used Flickerbook Review. Scanning through over 300,000 frames at high speed, we were able to track subtle movement that had gone entirely unnoticed in static thumbnail previews.
That movement changed everything. A child entered the frame, followed minutes later by an adult. Frame by frame, the progression became clear, something no still image alone could have revealed.