Watch Required Field (2016) Online

Serial killer 'NO1KNOWS' managed to elude the police for years. In fact they didn't even know he existed until, by chance, his video and audio recordings were found. By examining the recordings police were able to solve a number of murders around the world - although many men featured in the recordings were never found and it is unclear how many other victims there were since most of the video and audio recordings were destroyed (presumedly by NO1KNOWS himself).