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
I took a flight back from Europe with a colleague years ago, we talked for hours. A year later he was found guilty of killing his wife with cyanide.
People do a great job of hiding their demons in a professional setting.
Yup, can confirm, have a convicted offender colleague.