I totally get what you are saying but if the prosecution can prove she was murdered beyond reasonable doubt then it shouldn't be an issue. They must have the evidence in some form or fashion to have brought the charges without finding her. And if by some minuscule, miraculous chance the unidentified woman ringing doorbells is her, it's more important to find her and the murder charges would be mistaken anyway. There have been 100s of suggestions for who the doorbell ringing woman may be, I don't think it being suggested as a possibility would ruin any case they have against AH.