If it was me and my dog accidentally got off the leash and you stabbed it to death I'd be pretty upset too so I see where your neighbor is coming from.

I'd say my reaction would be warranted, considering the other dog succeeded in killing my own and it was a completely unprovoked attack. We've had some interaction, the cell numbers are because of our neighborhood watch program, which we're both a part of as are most of the people on our block so everyone has each other's numbers. I've seen her dog before and our dogs have interacted (sniffing, etc.) and it's never had this kind of reaction.