Roger Rogerson, a former police officer, killed Jamie Gao in a drug deal gone wrong. His well-publicised conviction was a huge story in Australia and left the nation in shock. Cops Who Kill lifts the lid on eight cases of murder and betrayal by police officers in Britain and around the world. In each episode, TV personality and actor Will Mellor is joined by experts, including ex-Detective Superintendent Julie McKay, psychologist Serena Simmons, and ex-Murder Detective Howard Groves, to try to unravel how and why a police officer switches from law enforcer to lawbreaker, how they were finally brought to justice, and the horrendous consequences for all concerned.