Stanley Gibson, a disabled Gulf War veteran, was murdered in a Las Vegas parking lot last December 12. He was shot seven times in the back of the head, without provocation, by a stranger wielding an AR-15 rifle. The killer, 34-year-old Jesus Arevalo, remains at large and is easy to find: He’s an officer with the Las Vegas Metro Police.

Gibson was unarmed. He was not a criminal suspect and posed no threat to anybody. His killing was a clear and unmistakable case of criminal homicide. Yet Arevalo has not been charged with a crime. He is on an extended vacation called "administrative leave," during which he continues to collect his taxpayer-funded salary and benefits.