Not just uncaught murderers, there are a lot of people who have killed without legally being considered murderers.
People who killed people in accidents such as driving accidents or hunting accidents
People who killed in self defense
Soldiers who killed enemy soldiers
Executioners
Police officers who have killed on duty
Doctors and nurses who have made mistakes that accidentally killed patients
There’s an early Robot Chicken bit where he dies and asks silly questions to a book that can give him an answer like how many times did I listen to this song, or how much of a wall could my poop make. This question sounds like an interesting one to ask that book though. Actually I’d probably prefer not to know the chaotic randomness that is our lives but guess the lives part would be redundant at that point anyways.