I hope no news is good news. I can't believe someone could be so heartless, cruel and just plain evil.
My only caution on dognapping her would be for fear of your own safety. If this man is this violent with a dog (and perhaps his family), I doubt he would have any reservations about seeing you "get what you deserve" since that's how he would likely think about it.
Keep calling the police / media / animal control and hopefully, they'll respond. You could always do the "neighbor-ly" thing and take over a plate of cookies to get a look inside the house. If there's more going on, a quick look at their living conditions will tell you and possibly give you more ammunition when you call the authorities. You might also get a chance to talk to the wife and offer her some assistance if you feel she needs it.
God bless you for taking a step to help this poor baby!