So I'll just make a really long story short..
There are people that live 2 houses down from me. They got a new dog about a month ago. Its small, it looks like a mini poodle. They keep it chained to their fence outside (on a very short chain). I've sneaken up to the fence about 5 times (lately) to give it food and water, because it has a bowl, but they never feed it or give it water. I know because the dog has chewed through the bowl (it looks like it did this a while ago), and its been in the same spot for all 5 days I've been there, but i know its been there longer. The bowl is covered and filled (the parts that arent chewed through) with dirt so I know for sure they aren't putting anything in there. Well on top of not feeding it or giving it water, the fur on this dog is HORRENDOUS!!! Mats and dirt everywhere!! I feel really bad for it, because over here temperatures have been as low as 37 degrees (at night) this month. And its a really sweet dog. Not aggressive or anything.
** Excuse me for saying "it" the whole time. I don't know if its a boy or a girl, but I will find out tomorrow morning when I go to feed it**
I want to just take it, and keep it, but unfortunately I'm pretty sure thats against the law.

(I'm not a thief).
What should I do? should I talk to the owner about the dog? Or should I just go straight to calling animal control? the cops? Idk what to do!! I don't want to have to keep sneaking in their yard. But I do want to help this poor baby.