there are two possibilities. one. the person who wrote this book is your murderer and acted out the killing described in ritualistic, literal detail. two. someone who wants to do the person who wrote this book harm read the book and enacted the killing described to incriminate the writer.
you're dealing with a devious, diabolical mind. this book must have been written at least six months, maybe years before it was published. that means the writer planned the crime, at least in the subconscious, back then. the fact that the writer carried it out indicates psychopathic obsessive behavior in terms not only of the killing itself but in terms of applied advance defense mechanism.
correct.
you're dealing then with someone so obsessed that he or she is willing to kill an irrelevant and innocent victim to place the blame on the person who wrote this book. we are talking about deep-seated, obsessional hatred; an utter lack of sense of proportion or perspective.
you're dealing with someone very dangerous and very ill.