The name of the dog behaviourist was not given so there is no way to know if in fact a specialist was called in by the SPCA, but assuming one was, we have little faith in any "expert" who will pronounce judgment on a dog that is in a cell after being on a chain. "Expert opinion" is an easy out.

Nor was the degree of the bites described, so there is no way to know if the bites were warning bites or serious bites, but since there was a second bite, then it stands to reason that the first must have not been serious, and that means that the second bite may not have been serious either, no more than the confusion of an unsocialized dog, suddenly in a strange, frightening place, surrounded by strange humans, and worse - strange dogs.

Justifications for any action are easy to find. Not betraying takes guts, and money, and a straight moral compass.