Sally Anne Bowman - Murder On The Doorstep

In 2005, Sally Anne Bowman, an 18-year-old model, was stabbed to death and sexually assaulted outside her south London home. Her boyfriend had dropped her there after an argument. But he wasn't her killer -- his DNA didn't match that found at the scene. A media appeal for help produced no suspect. Neither did a voluntary DNA-screening programme in the area. Instead, a brawl the next summer outside a local pub showing World Cup football led to an arrest and a chance DNA match that caught the killer.