Andrew Pearson kidnapped his ex-partner Natalie Harker before strangling, drowning and sexually assaulting her. In a distraught 999 call, he then tried to claim her death was an accident, leaving a series of clues as he spoke.

Ex-Commando and trained killer Collin Reeves stabbed his two neighbours to death after a long-running parking dispute. He claimed his actions were due to a mental breakdown caused by his Army service. But his cool and calm 999 call told a different story.