Six year old girl attacked in park

A quiet stroll in the park with her parents and little brother turned into a tragedy for a six year old girl as she was attacked by a particularly vicious dog. The dog, thought to be a terrier breed, attacked the girl out of nowhere and left her with severe injuries and scars. Scars which she will most likely has to carry with her for the rest of her life, she has however, undergone plastic surgery in a nearby hospital in Sussex. The owner of the dog quickly fled the scene after witnessing his dog attack the girl. He handed himself in at the local police station that day and has been arrested by the local authorities. 

My reaction

I wonder what should be done in this case. Will they put down the dog because it attacked a girl ? Will they arrest the owner for making the dog aggressive and being careless ? Or perhaps both ? I feel most of the blame is on the owner of the dog who was most likely aware of the aggressive nature of his dog and he should have been way more careful when walking his dog. In my opinion the dog cannot be blamed for what happened, however if it is found that he is too aggressive it might be the best if he is put down by a vet. Or maybe this is the perfect case for our dear friend from Animal Planet. 

http://www.bbc.co.uk/news/uk-england-essex-16669297