Fleeing Armed Robber Kills His Pursuing Victim, No Murder Charge? WTF?

This past Sunday a man decided to commit an armed robbery of clerk working in a California convenience store. When the robber fled with the stolen goods, the clerk retrieved his own gun and pursued, firing at the fleeing robber. The robber then used his own gun to shoot and kill the clerk. Many were surprised when Contra Costa County District Attorney Diana Becton then decided that she would not press a murder charge against the armed robber, on the grounds that the robber was acting in lawf...