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
Depends. Saw my dad die of mesothelioma (asbestos from being a Torpedoman 3rd class, WWII). Remember Dr. Dyson dying in T2? Like that but a bit worse. Stood by as a family friend had the plug pulled, nothing but a flatline.