Not usually for a first bite unless it seriously mauled someone. I highly doubt it was a first bite though. Healthy, stable dogs don't just attack completely out of the blue. There is almost always a previous incident or a gradual escalation of behaviour, growls, snaps etc.
If it really was a first time thing, I imagine the owner would be extremely concerned and taking the dog to the vets as the only dog I've ever known to have such a drastic, out of character episode was eventually diagnosed with a brain tumour.
This owner didn't. She bought a muzzle. This tells me this has happened before. People KNOW their dogs. My dogs are family. I know every facet of their personalities and if they bit someone, that would be exceedingly out of keeping with their personalities. Even provoked, they would not bite easily.
Ddog2 would, I think if someone was threatening or hurting me. He snarled once at a man who approached me on the street in the dark and started asking me random questions. Really properly snarled, teeth bared, hackles up, he looked pretty menacing and the guy backed up pretty damn quick. It's the only time I've ever seen him do that and I'm pretty sure the guy meant me harm. Dogs know. But otherwise, never. He's had children all over him, worked as a pat dog at a nursing home, I even have a photo of him somewhere with the hamster sitting on his head. If he went for a child unprovoked, I wouldn't be buying a muzzle, I'd be buying a brain scan and blood tests.
Ddog1 just doesn't have it in her. Not an aggressive bone in her body. Sweet and affectionate to a fault. Same deal, if this happened I'd be worried about her.
That went on a bit. Anyway, what I'm trying to say is if this is a first, I'll eat my dog walking hat and the police will make the decision about whether the dog is put to sleep and they will know whether there were any previous incidents reported concerning this dog.