I just want to chime in that I am so sorry for your pain and this horrific situation. Your children are lucky to have you.
My sympathy (perhaps empathy- though I hesitate to use that word because your situation is so much more severe) also comes from the fact that my boyfriend's ex-wife is an active alcoholic. She is not abusive at this level; she is emotionally damaging her kids through her actions and complete alcoholic mind-driven behavior. My own experience with restraining orders and court systems - in another relationship, and where it wasn't my children rather his involved- unfortunately rings similar to your struggles with the courts.
I hope there is legal and literal resolution for you soon, and ongoing support and healing for you and the children. As an afterthought- did you keep that policeman's phone number? I know that when I was trying to leave my abusive ex BF I had one officer much like the one you describe who I could contact by cell. If not perhaps you can follow up with him via the precinct and ask if keeping him "handy" is possible.