In my opinion, what that dog did was COMPLETELY UNACCEPTABLE, and if it were one of my own dogs, I'd be hard pressed to to kill my own dog with my own hands. However, I do have my temper under control, but I would seriously look at putting even my own dog down if it had the capability of killing another living thing so completely unprovoked.
The owner is responsible for that dog and it's safety and the safety of people and other animals that come near it and the owner should be punished as well as the dog. A dog like that should not be rehomed - it's too much of a risk.
I wish Canadian laws would change to make the owners of vicious/aggressive dogs answer for what their dogs did. Who's to say that this dog with a previous bite history isn't going to attack a small child next time. The risk is far too high for a dog that is a repeat offender to be given yet another chance to bite and/or kill.
Hey, we all love Rottweilers, but some of then are far beyond help and truly do not deserve it. It may not be their fault entirely if the owner was a loser anyway, but it's always the animals that pay in the end, isn't it?
Kristi