Darren McKie, a police officer, was convicted of murdering his wife over the debt he had put them both in after forging her details. He put her body into the trunk of her own car and stashed it away from their family home. Despite thinking that it was the perfect crime, his surveyor caught him walking home. 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.