Granada Neighborhood Association

They are filthy, loud and disposing all of their trash in the alley in stead of intheir own dumpster.  I have tried to call the property manager several times, and last night at 11:00pm had to drive to ask them to shut up.  They had three cars open with the stereos set to the same channels.  I've had it.  Only lived in my house since Spet. 07, and those apartments are a total disruption.  ANy ideas for how to deal with the tenants or the property owner?