A feature I’ve commented on in Golden Age detective stories is how often the detectives condone or even approve of suicide. To some degree I find this strange because of how un-Christian it is, in spite of the fact that England in the early 1900s was not really a Christian country anymore. Yet you even find this in Poirot, who is a bon catholique. To some degree, I suppose that it was simply part of the culture. That said, another idea has occurred to me.
It is often the case that in order to make the murder difficult to solve, the evidence which the detective uses to solve the is often… thin. At least in the legal sense. There is a tangle of evidence which the detective’s story explains very nicely so that it all makes beautiful sense. It is satisfying. What it often isn’t, though, is sufficient legal proof to obtain a conviction. One solution to this problem is to have the villain confess in front of witnesses. This can be hard to pull off convincingly, though. Why go to all the trouble of trying to frame someone else for the murder in order to get away with it, only to confess in the face of legally flimsy evidence? There is a second solution, though. If the villain kills himself it obviates the need for legal evidence of any kind, and killing himself is not the same action as confessing. To confess is to guarantee that one will be convicted and hanged with all of the social shame and anxiety that entails. To kill oneself can be portrayed as the murderer hedging his bets. It’s easier to pull off, I think, when the murderer’s social status would be destroyed by the detective spreading the word that he did it, even if no criminal conviction could be obtained, and the murder having been committed in order to gain social status. It can be done “offscreen,” too, which means that the reader will probably not examine it as closely.
I should note that there is a humorous Mitchell & Webb sketch which contains this idea. I had seen it many years ago and remembered it after I thought of this the other day: