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
Yes. I used to live with a guy who worked for a penitentiary. He had inmates over who were on leave. I’ve met people who killed their parents in cold blood and had dinner with them.