The idea to tie a string to a rat is reminiscent of a short story by Jacques Futrelle about a private detective/mystery solver called Professor van der Dussen also known as "The Thinking Machine." In the story called "The problem of cell 13," van der Dussen bets a friend he can do anything, and his friend dares him to escape from prison. He does that developing a plan, that, among others, involves tying a string with a message to a rat, and letting the rat run it outside through an old drainpipe.