Most victims of murder know their killer. But when a violent crime is carried out by a complete stranger, it can often be much harder for the detectives to solve. In Watford, police found themselves on the backfoot when a womans body was found in a popular local park, with no immediate clues as to who was responsible. This episode reveals how a fleeting sight of a man running across a nearby motorway put police on the tail of a dangerous killer. And it probes how the efforts were initially thwarted as their suspect went into hiding. With contributions from the main detective and from local residents and reporters, this is an episode that gets under the skin of one of the most tragic episodes in Watford’s history. (thetvdb.com)