As I type this, on the couch next to me is rescued Rottweiler happily snoring away.
Rescuing and adopting is a wonderful thing. Folks need to pay particular attention to the temperament of the animal, and forgive me for stating the completely obvious, particularly when they are the powerful and headstrong breeds.
Unless you have had and or know and or are a trainer / pack leader type you should stick to the breeds you know when adopting.
A tragic end for anyone. And particularly for a good caring individual such a s her.