Exactly. But this also means they aren't really serious, since they haven't caught you. Get some pepper spray and train them to keep their distance if you really feel threatened.

Another option would be to get the owners phone number and ask them to lock up the dogs when you are going to be running by.
EDIT: Oh... you've already called the "cops" on them. I think that was a big mistake! I don't understand this behavior unless you want to make enemies. Talk to them like a normal human and be nice. I've found that pretty much everyone is reasonable if you show a little friendliness and respect.