Hi Leonardo! Perhaps the statue you saw was in Baker street, London? That's the place most associated with Sherlock Holmes, and there's a statue of him near the tube station. You can see it here

There's another, better (I think) statue in Edinburgh, in Scotland. That's where Conan Doyle, the writer of the Sherlock Holmes books was born. You can see a photo of the statue here

I don't know about the bookshop, but I know that mystery novels are so popular that there are lots of specialised bookshops. I love mystery books and detective stories. In fact, with my students (I am an English teacher in Barcelona, remember!), I sometimes tell them a detective story I have made up that has no ending (I couldn't think of a good finish to the story!) and ask them to finish it for me. All of the endings they write are completely different and very entertaining!