There's a very aggressive pit bull type in my area, it tries very hard to get to any dog in sight, and threatens humans too - the only thing that stops attacks happening is the owner, who has a constant tug of war with it. The owner is reputed to be a drug dealer.
This particular dog is a disaster waiting to happen, and something needs to be done to stop it - but what can be done? I've reported it to the police, twice, and they've done nothing. Other people tell me that they have reported it too, with the same result.
I sympathise with the police, to some extent, because it's very difficult for them to prove that any particular dog is in fact a member of a banned breed, and they just don't seem to want to put in the necessary resources, but at the same time I see it as being their job to do so, to protect the public. Problem is, every time someone gets killed by one of these dogs there are always neighbours who say that the dog was a menace but that the police ignored all complaints. But, I suppose it's all about resources - if some police forces aren't able to deal with girls being sexually assaulted in their area, then they aren't going to give priority to dealing with dangerous dogs.