I'll overlook your tetchy remark, Katiebee. The reason I was asking was because I suspect your friend and her family are probably foreigners? In which case it would not be unreasonable for someone to seek help on their behalf, that's all. I may, of course, be wrong.
They also have recourse to their local Citizens Advice Bureau which can provide free legal advice. Well worth considering.
If your friend lives in England, for example, as opposed to another UK country, the housing associations are governed by a body known as the National Housing Federation (NHF).
The attached links may be of interest:
http://en.wikipedia.org/wiki/Housing_associati on
http://www.housing.org.uk/default.aspx
Your friend appears to have been fobbed off by the Police whose remit is not to act as Judge and Jury, their responsibility is to investigate such allegations, gather whatever evidence is available, and present their findings to the Criminal Prosecution Service (CPS) which is the body tasked with bringing prosecutions and who are the ultimate authority on whether to prosecute or not.
I'll give you another link which may at least be of interest and is on the subject of Mediation which is a relatively newish concept in the UK whereby local authorities can appoint such a Mediator to try to resolve neighbours' disputes for example. It may not be the answer but is worth considering:
http://en.wikipedia.org/wiki/Mediation
I hope this information may be of help. Good luck.