Trouble in our Fur Family!

Is that right?

We recently had an unexpected, and unwanted, event with our Fur Children. Our little white female, Bella, suddenly attacked our yellow Lab, Sandy. Sandy is almost twice the size of Bella, but much more laid back. She was completely surprised by the attack, but tried to fight back. Unfortunately, both dogs were on leashes and I was holding both dogs. Somehow Sandy lost her footing and fell over. Bella went in for the kill. Before we could break up the fight Sandy had received multiple puncture wounds and was in a terrible state of shock. She had to be taken to the vet’s office. My wife also received a bad puncture on her hand.

We have been keeping the two dogs apart now for probably 4 weeks. But every time Bella sees, smells, or hears Sandy she shows that she is ready for a repeat encounter.  Bella is probably some kind of Terrier mix and there is a lot of negative literature  about how difficult it is, if not impossible, to get these two kinds of dogs back together.  Any experienced dog owners out there that have any suggestions as to how to successfully reunite these two dogs that used to be best of friends?