The Washington Post has this story about what makes a dog dangerous under Virginia law.
I did once represent my sister's dogs Buck and Summer in dog court in Washington County. They were observed at the scene of a dead cow. The farmer would have shot them if he had been closer. Instead, they ran off, so the farmer took a warrant. My brother-in-law paid for the cow, we got a little release from the farmer, and Buck and Summer were put on good behavior. I think Summer was given away. The mellow dog Buck is still around, relocated with that family to Lee County. It was one of my best cases ever in general district court.