We needed a crime. In order for the story to work. What did we mean, work? For whom does the story work? Not the victim, whether she be hung by a belt in the closet so no one would suspect homicide by the gardener, whom she loved once; or a man mowed down by a bus, it's a shame but it happens sometimes, people will say but will they guess that the driver owed him a fortune he would never be able to repay?
No no we are wrong. The story works for the victim too. Without it, she makes love in the garden one last time and is shocked at how few years need to pass before the details of that time are forgotten. And meanwhile the man makes it across the street, the driver lets him pass and the debt is perfectly ordinary, that is, invisible to literally almost everyone.
And the killer? Well it's clear to us what he gets. And we will be secretly rooting for him, even up to the moment when he is finally (inevitably) caught. His action took him to a place in which whatever he does, no matter how ordinary, will seem charged with meaning, electric, which is why he must be punished; but only after we get what we want from him.
And what about us? We get the chance to both be away from lives and deep in them, feeling everything--