Mystery in London

It's best bools every book review I read. First, this is main Hero is me! One police came to my house and asked me to help for Whitechapel killer. And I visited some places and some people, And there I can collect a way to solve this problem in this book. A or B or C, I can choose. But I make a mistake, I have to go back first page.... So I could help in this book! Finaly I could solve one mulder(85 words)