Gabriel Knight: Sins of the fathers. 20th anniversary edition

The words were written by Gabriel Knight, a man who had sins of the fathers. There is a remake of a tale about legendary Gabriel Knight who investigates uneasy cases. The main character is the owner of the book shop. He sees horrible things happen to him and he is very afraid of it. The city is concerned about killings based on magic. The hero wants a deeper look at what happened. Help the character find needed evidence and answer all the questions.