The Solved Case of Rachel Nickell

In 1992, Rachel Nickell was out for a walk with her dog and 2 year old son on Wimbledon Common in London, when a man came out of the blue and stabbed her to death. She was found with her son by her side, holding her hand. What followed was a shambles of an investigation by the Met Police, in which they decided to focus all their efforts on one (innocent) man, as the true perpetrator went on to kill others.