Documentary following teams of detectives and specialists involved in murder investigations. In the early hours of the morning in Droitwich Spa, Worcestershire, a 999 call is made by Mohamed Samak saying he has found his wife Jo in their home with a knife in her stomach. Despite attempts to resuscitate her, Jo is declared dead at the scene and the officers arrest the husband on suspicion of murder. But as the investigation continues, the overall picture is more suggestive of suicide rather than homicide