I thought it was a tad strange that both their children had been murdered and that they were sitting down to a cooked dinner - don't think most people would even be functioning.....
I enjoyed it, though I found some parts at the beginning a bit confusing. The boy and girl, son and daughter of the two families, had been murdered. The nurse we saw at the beginning is the sister of one of the murdered couple - but who was the old lady she was nursing, who wanted to give her the antique ring, and asked her to help her to commit suicide? Was she related to either of the two families?
I don't think it was mentioned who she is although I wouldn't be surprised if she has some kind of connection, the nurse was nervously fiddling with the jewellery (I thought it was a spider brooch) in the house, as if drawing our attention to it.
Just caught up with this. Really good. I think that the couple think that it was their son who did it. As it seems something has happened in his past. Don't think the druggie did it - but he recognised the bride in the photo I think. Too many thinks, methinks!