My neighbour neglects her 7 month old kitten - HELP?

I dont know what to do - my neighbour was given a kitten by her brother - she does not seem to look after it very well. During the cold 5 degree nights just this last winter - the kitten was always finding its way into our shed. It went on for most of the winter. I took the kitten back to her a couple of times - and asked her if it was being fed properly and was it deed. The second time I took it back to her - I told her it was not the way to treat an animal. It is skinny, it has killed 11 birds in the last 7 weeks. It is not left any food or water during the day. Come the weekend - Emily disappears for the weekend, and the cat is always hanging around my house. It was eating a peice of bread that was out in my backyard. It balances on the edge of my above ground pool to get a drink. It has jumped from the top of my shed onto an outdoor umbrella (and ripped a big hole in it). It always kills birds and leaves them in my driveway. Emily is away from 7am till when she finishes teaching. Emily is a primary school teacher and she is 26 years old. She does not give a damn about the cat. It climbs up on my front door screen trying to get in and the cat screams at me when I try to move it away from my front door. Help please. What should I do? This animal deserves much better than her. I do not want a cat personally myself. My main concern is the neglect, and all the birds it has killed (including a whole nest of baby birds). I am really upset that this kind of behaviour on her behalf is occurring. Does she not realize that cat will live at least 20 years. On one other time that I took the cat back - she locked it inside for 3 days. I have heard her yelling at the cat - to get of the bench. I have also heard her throwing plates, gles (or whatever) when her boyfriend (ex -now) found out that she had been screwing around. He was going out with her for over a year - and they had a mive brawl lasting for 3 hours - with him calling her a slut, over and over again. But my main concern once again is for the welfare of the cat - it does need to be treated humanely. Any good answers or solutions would be good. I thought I would have had a solution - but I seem to be fighting my own little war.