I think the killer left his handwriting feeling he would NOT be a suspect - - that he would NOT be asked for a sample.Uneducated or not, I don't think LHP is THAT stupid to think no one would ask her about the daughter of her employer being gone. I don't think she would have left any note.
BUT - - we know that LHP and her husband and her daughter and son-in-law had done work in that house - - KNEW the house - had access to the amount of the bonus ($118,000) if they chose to snoop at all. If they were with friends, I wonder if THEY would have talked about the "fat cats with the little pageant princess" who lived in Boulder. Why, here they were scrounging to pay for rent money and JOHN (the fat cat) got a BONUS of - - you won't believe it!
Maybe THAT person got them to talk about the house - the many rooms, the work they did there - - like the broken window Mervin was ASKED to fix in the basement.
Could that be our killer?
I think it is a reasonable possibility and the housekeeper and her family shoulf have been asked about that - - but it seems that didn't happen.
I would LOVE to have a copy of the early interviews of the housekeeper and others.