Good read. Most people don't know that new York city had it's own zodiac killer.
He had a schizoid personality - they don't need much in the way of personal relationships with others.
He made his own zip guns - homemade gun out of metal tube that can fire one bullet. He would go out at late at night night and shoot some random person walking alone.
Police had no idea who he was until he shot his sister in their apartment one day, and she called 911. She didn't know he was the zodiac.
He then started shooting out window of apartment.