Personally I would not point fingers. It may have just been a freak accident. Without any proof that is a horrible thing to say someone did. Could your grandmother bring the dog in for a necroscopy? I'm sure they would be able to determine the cause of death.
I'm so sorry this is just terrible. Last year my Stormy passed away and I was so upset over her death I was blaming my husband for it because it happen while I was not home that she died. It was terrible of me to blame him and he was very very hurt by my accusations that he just "let her die". When I came home after getting my frantic call from my husband was about 20 mins or so and for all that time he was giving her CPR she was long gone and he just couldn't stop he said because he knew how much I loved her and how devastated I would be.
I just wanted to share this so perhaps you could understand that maybe it wasn't done on purpose and it is just hurtful to say someone let the dog die or killed it. You just never know. Again I don't know the people who live at your grandmas but I'd like to believe they wouldn't of killed the dog.
