This is a tiny too-young 6-week puppy.
I have a feeling, the puppy was there and found a plaything and kept gnawing at it, even as it would move a bit and cause extra interest. The baby’s mouth could even have emitted smells such as milkiness that would be interesting to a dog of any type but esp. a puppy.
I sort of doubt this was all about “viciousness”. The puppy is too young to leave its dam and may especially try to keep feeding on a soft rounded milky moving thing it found.
I despise pit-bull terriers, but I sort of doubt that was the real cause here.
Highly negligent parents - gee, I wonder why?
I checked for photos before I posted but the pictures that came up didn’t look right; checked just now for the two breeds separately at 6 weeks. It’s just way off unless the puppy was older or even mis-typed as weeks instead of months. Even a pit bull puppy’s mouth is on the small side to bite a baby and the baby not be able to scream in pain. Unless the dog smothered the baby because of food still on the mouth or even spit-up that happened while the parents were sleeping. I hope they do an autopsy to determine the basic cause.
Although a lot of people love their pit bulls and pit mixes, I’m very leery of them, but I don’t want a dog to be accused of something just because of its breed without it’s individual behavior being taken into consideration.
Teething puppies shouldn’t be around newborns while parents are asleep, no matter the breed anyway, and parents shouldn’t sleep with a newborn baby who is so easy to smother.