An unsuspected suspect

The man who killed at least 59 concert goers and wounded 500 was said to be normal. While we cannot be suspicious of everyone it is hard to believe that this man was considered normal. A gunman isn't normal, my original thought was that he was a disgruntled veteran. He was very good at striking targets from long distances. He also converted a semi-automatic into a machine gun and owned an arsenal of guns. To me the hint was that he had no connections with a religious community, a social group, a recreational group, and was not tied to anyone, maybe an ex-wife. People do not really notice things because they are wrapped up in their own busy lives. I wonder why people didn't realize that he was a real loner. There must be more not everyone just does this at random.