How do you go about writing a detective story?
Well, you forget detection and concentrate on crime. Crime's the thing. And then you imagine you're going to steal something or murder somebody.
Oh, is that how you do it? It's interesting.
Yes, I usually put myself in the criminal's shoes and then I keep asking myself, uh, what do I do next?
Do you really believe in the perfect murder?
Mmm, yes, absolutely. On paper, that is. And I think I could, uh, plan one better than most people; but I doubt if I could carry it out.
Oh? Why not?
Well, because in stories things usually turn out the way the author wants them to; and in real life they don't... always.
Hmm.
No, I'm afraid my murders would be something like my bridge: I'd make some stupid mistake and never realize it until I found everybody was looking at me.

