Violence detection using OpenCv or Tensorflow on CCTV feed

I want a python program (preferably working with opencv) that can take CCTV footage's output video as it's input (or any video as it's input) and track the human activities going on. Also, if the situation becomes violent, such as fight or accident happens, I want a system (PC) to make alarm notification. If the program requires GPU and CUDA, then documentation of how will I execute the code on my GPU is also preferred.