"The locked room is an exercise in illusion - a magician's trick. Otherwise it's impossible, and the impossible can't be done, period. Since it had been done, it must be a trick, a matter of distracting attention, and once you know what you're really looking for, the answer is never hard."
- Michael Collins Nobody Likes To Be Played For A Sucker
The above quote comes from a short story by Michael Collins carried in a locked room anthology edited by Edward D. Hoch. The solution to Collins 'locked room mystery' is one of the more ingenious and believable ones in the book. Locked room mysteries are a lot of fun!