Aww Blu, I am so very sorry.
Its a horrible thing to have happen.
Last year I took in a stray dog, she was with us a few months and got along great with our other dogs so we decided to keep her.
One day we came home from shopping and found that she had torn apart and killed one of my dogs.
It was a nightmare scene for sure.
I had to take that ex-stray to the shelter and I am sure they put her down. It was the hardest thing I ever had to do...even under the circumstances. But she could never be trusted again.
Even now it brings tears to my eyes thinking about the loss of both dogs. Its very hard and will take time to heal.
Hang in there ok? *mega hugs*