The story doesn’t mention whether the dog was a pitbull but I would lay odds that it was. The owner ought to be prosecuted.
No the dog was probably a "migrant" or an "undocumented worker" and yes the owner should be convicted of manslaughter or negligent homicide or whatever the legalese is for causing an unintentional death by his/her actions.
I wonder how often dog owners are successfully prosecuted for negligent homicide when their dog mauls someone to death. Probably not often enough.
As far as I'm concerned an incompetent dog owner whose dog kills someone is just as responsible for the death as a drunk or incompetent driver is for vehicular homicide (i.e. involuntary manslaughter conviction).
If the dog has a history, the bible says the owner should be stoned.