I cannot even imagine who would do this. Or why.

Whoever it is, they need to be caught ... because I would bet any amount of money that this person goes on to do terrible harm to people next. There is something not "right" about people who do things like this ... and the next step in the progression is usually murder.

It really struck me that this girl lives with her grandmother. For whatever reason ... death, drugs, abuse ... she does not live with either of her parents. I would imagine she felt very alone and depended on that dog very much.