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
It’s going to depend on their condition. Someone who has lost their respiratory drive, someone who has a heart that isn’t working, and someone who is dying of organ failure all have their unique way of passing. And those are just the ones I’ve seen. There’s a saying in my field that everyone dies of shock, but there are lots of ways to get to that point.