Contact your local council first.
They will ask for a few details, then probably ask you keep a diary of events,....times, who was involved, witness, that sort of thing.
If anything really serious happens, always call the police straight away and never get involved.
Councils and authorities alway react better to police details, remember to get crime nos.
This could take months of surveilance, but keep at it.
Petitions could be difficult to get, as you could end up being their number one target.
I really feel for you.........been there myself, and still fighting after a year!!!!!!
I hope this helps