What do you think made this dog attack, and kill.?

That's a terribly sad story, I don't know what triggered the vicious attack from the dog, but I bet it's not had a great upbringing.

The family got the three year old dog six months ago, so it's background would be the reason for it's behaviour. It most likely was abused by it's previous owner, that's why it's unwise to get such a powerful dog when it's older.

My fiance had three border collies from when they were puppies, he raised and trained them, they never bit anybody and were very well behaved. He told me he'd never take on any dog unless it was a puppy, as it's very difficult to retrain an abused and violent dog, it could turn anytime.

Hard to say for sure but if the dog came from an animal shelter, he might have been mistreated as a puppy before being abandoned and saved by animal welfare workers. If a young puppy is mistreated, there's a higher risk that the dog will grow up to be aggressive and paranoid through ingrained experiences.

Alsatians, are inbred and unstable. A bit like their owners. For this reason the police in Britain have stopped using them, and train dogs like rottweilers instead.

The same sort of thing has happened to golden retrievers, and the guide dog people now use different breeds.

dogs attack out of fear or stress or a sudden movement provoke a predator response. I couldn't read the article as it wouldn't load.

savage dogs are a result of bad upbringing and irresponsible owners.