I’ve got no time or patience for violence threatening punks. Discreet cameras may be of value but I’d have no hesitation mentioning this to police so they are aware. If you call it in numerous times I imagine they will pop by of their own accord, and if they need to repeat this she will get short shrift should they return. That necessity to involve cops by reasonable people will also work in your favor as the other owners won’t be happy to be known to live in a block that police need to call to so will want the issue sorted quickly. Also, have you been in direct contact with the owner? They may not be aware of the issues their kid is creating and just may move in your favor to halt her line of poor behavior. Also, sounds like though you live your own lives you likely have by-lays in existence so are bin protocol etc already mentioned in these which can easily be enforced/reminded to all owners so it isn’t just felt focused on her? All the best with it all.