Does anyone care when dog kills dog?

Last week a lady was walking her small friendly rescue dog on a lead on the upmarket housing estate that is near my shop, when a large dog (American Bulldog type we believe) came from nowhere and took the little dog by the neck and dragged it off into the bushes ..... apparently the little dog was killed, but the dog ran off with the body.
The distraught owners rang the council (dogwarden came out, said they couldn't do anything as it was quote "dog on dog".) Rang the RSPCA (didn't want to know - no surprise there!) Rang the police ..... very little concern, nothing really done ... again "dog on dog" didn't really seem important to them?
The people found out where this dog lives (it has attacked other dogs in the area over the past couple of years) - went round with dog warden but the people wouldn't let the dog warden into the garden to see if the body of the dog was there, and were not willing to talk to anyone - certainly no apology or remorse. They said that the dog in question was no longer living there .. we believe it has been sent to stay with friends for a while, and apparently the people have now told the police that it has been stolen!
Everyone on the estate is horrified .... people are afraid to walk their dogs now, and say they won't even let their young children out to play on the estate. There is a petition which everyone is signing to give copies to the council and the police - asking for something to be done so that people feel safe again. My shop is a focal point for all this activity, as all the local dog people come here and use the shop to pass on messages.
So what is the law? Everyone is saying that the dog must be a danger to children as well as to other dogs. Where do we go from here?
Advice welcome.
Mary Sanders