I don't see how it could be an accident that the puppy ended up in there, but I'm also not going to completely assume it was done intentionally or at least I'm not going to assume it was done maliciously. A child could certainly do that without knowing the dangers it posed to the puppy. My friend's child accidentally threw the family's hamster away once.

Anyway, the reason I'm not going to automatically assume this is a case of horrible cruelty, is because there are already plenty of those cases out there to make me ill. I'm just glad the puppy was found and will hopefully have a good forever home soon.