seriouss ethical need

this is a long message and i am apologetic for that . i have to set up the picture of this in order to have a better understanding and better help with it so i am left without a choice but to write alot .i have a question and i am not sure where to go with it i alos tried yahoo answers and would like to try here.
i am in a bad situation. i have two neighbors on either side of me and live on a short street, well my one neighbor next to me moved away and keep that in consideration for what im about to explain. my other neighbor and i were fairly close she went through a bad marital situation and has a 2 chidlren one who is sick a lot of the time . she appears to be a nice person and a few times i have watched her kids for her while she does errands and etcetera and she sells avon and i have bought from her, she seemed really nice just unorganized and flustered .her house smells like cat pee really badly and she lets the kids make messes all over the place and doesnt blink when they spill things like milk into the rug and stuff that will smell terrible if not cleaned properly. you know, im just trying to paint a picture of her. moving on- her husband left her for another woman and was living with another woman in an apartment and she has done some crazy things like one day i noticed a huge flame outside and she had a bonfire going with all of their wedding pictures, and some of his belongings that was a huge fire, and was dangerous in size to be going on between two homes even though they are about a half a football field apart , note that we dont live extremely cramped close theres a bit of grassy yard and her gravel driveway between us.
so my point is she isn`t all there at times and is taking this seperation really hard. well here the man is apparently living there again since christmas which is outrageous to me wow- wow- wow is all i can muster but my concern is with her dog. she `inherited` a dog from someone and has the damn dog tied up out in her back shed and he howls all day and all night, she throw`s a whole bag of dogfood at a time -i am talking the 25 pounders- into a bowl for him and doesnt come out again for days to feed him or check on him. and i have often had to go over and check his water bowls, food bowl, and make sure he is not tangled.

it has gotten Better since the summer time at least when i was infuriated to find that she went camping for a whole week in the dog days of summer and left the dog tied up on a ridiculous about 30 to forty foot cable line n he got himself completely tangled in trees and bushes that were all around him. when i pulled up from being out he was pantin and cryin n howling in complete sun exposure and this was about 1 in the afternoon! he had a lot more time to go like that and if i hadnt come home i mean i swear he could`ve passed away that day and died a miserable death and i am So infuriated by it that i left her a voicemail that she took as `offensive` -she didnt tell me to my face she told my brother who also lives with me temporarly he just moved in from california and is buying a house -and the vmail really wasnt half as bad as i would have left if i didnt know that she is capable of a lot of trouble if crossed and has been in the past for people. i just stressed the situation in my vmail and that he could have had heatstroke if i hadn`t come home when i did. the dog is a collie mix and has the coat of a rough collie for crying out loud!
it has been an ongoing struggle with this dog i have checked his water and food everyday for the past half a year and she ended up putting him on a run that he cant get tangled in after i left her the voicemail, but i am disgusted now with the fact that i literally am losing sleep each night as the dog howls just outside my bedroom window. he was even out howling in the RAIN on a very very cold night. i was so disgusted but my problem is that if i call the humane society, she will KNOW that it was me who turned her in because the other neighbor moved away so its really just myself there with her - we live on a residential street with not that many homes on it, its just a very short street that diverges onto another. in my heart i know that i have to keep checking on him. i have thought of mailing her anonymous posters from dogs deserve better on bringing chained dogs inside. i do know that the dog has a BAD problem with urinating and marking everything in sight, when he got loose one day as he has done many times, i opened the door and he came running in and sniffed and lifted his leg right on my sofa. hes a great friendly beautiful dog with the temper of a sweet kitten and great around my dogs who can be a challenge to deal with- and hes just great. i feel terrible.
i am at a Loss of what to do here. i know that it could get really ugly if i turn her in and i just cant risk it have a child to think about and just i absolutely cant risk anything happening at all and she has told me stories of things she did to exs in the past of destroying property and i just can not risk anything im not in a position to move. i feel as though judging from other areas of her life she is not in a stable emotional state and i feel like i own an outside dog now that breaks my heart and when he howls all night i want to let him off the chain and have thought of it but i think of cars and i cant do it. if something happened to him i would be ravaged. i have suggested she give him up but she claims the dog is sentimental to her because of the person she inherited it from but it seems crazy to me just crazy and such a lie. no matter whats going on you dont treat a living animal with neglect like that just mental and emotional neglect. he was very thin in the summer and i knew he was eating because i fed him if she didnt and i was the one who had to buy damn wormer and give it to him and finally he put on some weight. she get`s very offended everytime i offer to take him to the groomer or vet for her and gets an attitude anout it and like i said i cannot chance her revenging me in any way and the police are only there after the fact so they dont help much in this situation.any kind suggestions please let me know. i would have no problem turning the person in if i knew i could move from the area after but i cant do that.