When the mutilated remains of a young child were pulled from the River Thames on September 21, 2001, one of the most complex, bizarre and high profile murder investigations in criminal history began. All that remained of the tiny boy was a torso. His head, arms and legs had been removed with chilling precision and his body had been drained of blood. Identification seemed almost impossible. The lack of teeth and fingers rendered standard forensic techniques like dental and fingerprint analysis useless. Detective Inspector Will O'Reilly, of Scotland Yard, was charged with leading the investigation and turned to science to advance his inquiry.