Nick Storie; A Sudden Silence

A very popular man, the neighborhood wailing wall, is murdered on the street. There isn’t a single clue to grab onto except one of those sudden silences that happened when the shot was fired. When Nick solves that one, it really gets hairy.
Nick meets another set of powerful gangsters, who he befriends. He solves the case, being shot at in the final arrest.
Then he gets a call from the gangsters. This one isn't over. There could be a gang war.
Nick has to be pragmatic to a degree he never wanted to appear.