All I could think of when reading this was something my husband told me about his Jack Russell, Chance, when he was a teenager. A German Shepherd from across the road grabbed her, shook her and threw her. Thinking it had killed her he waded in and started kicking the GS before it went for her again. The owner came out, having missed what had transpired and of course wanted to know why he was attacking his dog. The owner apologised once he realised and thankfully Chance was physically unharmed, but in shock.
It makes you realise the extent you'll go to, to protect those you love. Hubby was only a slip of a lad back then.
That's funny, only because I used to have a chocolate lab named Chance and a Jack Russell named Jack. Jack would attack any other animal, completely unprovoked, so when he got beat up, it was definitely his fault. A horse kicked him when he went after it in the stall and broke his hip. Once he was healed up he went after it for revenge and almost got it again.
A few years ago our neighbour's German Shepherd attacked her son's dog, A yellow lab named Chance and put several puncture wounds in his neck and chest.
Just coincidences, but when I read your comments, I sort of drifted into the possibility that "A Dog's Life" might be true and your husband's dog might have instigated the attack subliminally to have your husband do the dirty work.
Lol! Had he not seen the entire event I wouldn't have put it past her! When I was first introduced to her I put my hand down to stroke her and she, snapped, yelped like I'd hurt her and gave hubby puppy eyes! He thought it was hilarious. She would never have hurt me, but she always got jealous of new people getting his attention. It took months, before she'd let me touch her.