[celstu1]

I know what you mean. I was SO angry when I lost my Stuart.... well after I got over the shock and initial grief. It just made no sense. Even worse was I never got an explanation. I had a necropsy done that told me he ingested rat poison. That was it. I had no idea where he got it (not in my house that's for sure), when he got into it, (they told me some take weeks to work, some take days), I was ANGRY with nothing to direct my anger towards.
Write your neighbor a letter, pour everything out into it, all your anger and grief. Then burn it. They say this is very cathartic. You could try writing him a letter actually telling him how upset you are with his lack of compassion, that his dog killed yours and he showed absolutely no remorse while you have been heart broken, a letter you could actually put in his mailbox.

I'm a firm believer in getting emotions out, getting words out, and getting them to the person who they need to be directed at. I don't mean mean, hateful words, I mean truthful, honesty spoken in a mature, non-confrontational way. I think that is always the best way to 'clear the air' so to speak.
(((HUGS))) to you! I know this is a nightmare to keep having things play over in your head. I know too well what you are going through.