In 1986, Sherri Rasmussen's husband found her shot to death in their LA home. The case was quickly shelved as a robbery gone wrong. But with the advent of DNA analysis, new evidence emerges which shines a light on a cop with a dangerous obsession. 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.