Truly a sad story.
But as an owner of a 2 year old pitbull I have to disagree with GOB"S solution. I have 5 kids ranging in age from 7 to 20 and my dog is the best family pet I have ever owned. I have had Great Dane, Bull Mastiff, and many a Doberman and German Shephard as a kid. My father Scgutzen trtained dogs for the military so as a child I spent time with dogs hanging of my arm as well.
Pit Bulls are not overcrazed aggressive beast. They are actually very well adjusted for families and if handled correctly make wonderful pets. My kids can lay on, play tug of war with him andf even snatch food out of his mouth when he is eating. This dog has NEVER SNAPPED. Not once. Try that with another favorite bread and you might not like the result.
The problem is pit bulls are very tenacious and are natural pullers. They love to grab onto things and pull them. I have a rope hanging off my tree with a knot and my dog will swing from it holding on by his teeth with my sons pushing him. He will play tug of war and drag them across the yard.
My dog is also very good around other medium and large dogs. I have a friend who trainsBlack labs for bird hunting and my dog loves to go run around with the 7 or 10 dogs he has in his pen. Once in a while one of the alpha's will attack him, and my dog will react with a very convincing argument. We break it up and things cool down. Like Mick said earlier this jaw locking thing is urban legend.
One thing I will say negative about the breed, because I'm not a piut bull homer by no means. I have noticed that my dog does find small things vert enticing, birds, squirrels. cats, possumns and the such. Even on lead I have to strong correct him when one of these pass his sight. Something with the size and the way they move drives him nuts. Other than that I have had a wonderful experience with this breed.
I just think people need to be more responsible and know their pets. Dumb people shouldn't own big dogs and most of these are the same people who shouldn't have kids either. JMHO