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
Met a guy after he got out of prison for drunk driving and killing someone. I don’t know the details but he wouldn’t go anywhere near alcohol, so at least he’s trying to be better.
Also I have met quite a few War Veterans over the years.