David writes "DEATH" on Vicki's mirror and is forced to confess that he did it and not the widows.
Did David actually admit to writing on Vicky's mirror? I don't think he did, any more than he admitted to taking the bleeder valve out of his father's car or breaking his aunt's teacup. There always remains the possibility that David didn't do any of these things. It's a very slim one, but it's available to the writers.
Incidentally, I noticed that we never did see the mirror after David set out to erase "DEATH" from it. I had my doubts as to whether he could reach that high without a stool. And then when Vicky was doing some more erasing, we didn't see the mirror either. What was used to write "DEATH"?
Roger seemed quite happy when he came home. I assume he had been drinking rather than going out to see Bill Malloy's cousins, whom he probably could have telephoned. I suppose he would figure Elizabeth wouldn't bother to check his story, or else maybe he's drunk a little too much too care.
Joe gave Carolyn a watch for her sixteenth birthday. It looked like a nice one, from what little we saw of it. I'm surprised he had the money to buy her a nice watch. By the way, was it for her sixteenth birthday that Roger gave Carolyn the ring that she accidentally on purpose left with Burke?