In the early hours of Saturday March 29th 2014, the body of Jim Attfield was found lying in Colchester’s Castle Park. The father of five had been stabbed 102 times. Three months later, 31 year old Saudi Arabian student, Nahid Almanea was attacked in broad daylight on the Salary Brook Trail. Both victims suffered multiple wounds and were stabbed in the eyes. Nearly a year later another attack was thwarted. This time the police caught the suspected serial killer, only to discover it was a 15 year old boy called James Fairweather. In this episode, Jo Frost speaks to Jim Attfield’s mum Julie Finch, criminologist Liz Yardley, neuroscientist Dr Francesca Happe and criminal justice expert Malcolm Stevens to find out, what leads a teenage boy to start killing strangers?