It's possible that she left this "evidence" there on purpose, her final comment on life before she died. It's not much of a will, but perhaps it's still an important legacy for the townspeople, whose parents had cruelly interfered in Emily's happiness, and who themselves further isolated her out of fear, disgust, and general spite. Everyone pitied Emily, but that's a lot different than loving her. What she left them was the legacy of just how human she was, of just how much she wanted love, and just how warped and twisted the desire for love can become when it is declared off limits.