I'm not usually for mass surveillance, but I've seen reports of successfully altered behavior by cops who wear body cameras. Perhaps it would be a good idea to have all cops wear such cameras as a mandatory prop as long as they're on duty.
It is a good suggestion to keep the cops under surveillance. But is it practical to make all of them wear body cams? The initial cost, as well as maintenance will be huge. And there is no guarantee that they will not damage / tweak them. Also we need more manpower to manually monitor all of them.
There are many things to take into consideration. But given that cops in general would behave better, and that less civilians would get shot, I think such a system would be a good idea. In the cases were a cop is alone with a suspect, the cop is God. With eyes on him, he would no longer be God.
Of course there're challenges in regards to logistics. I guess a more scientific report could give better results. As the situation is, I think wearing bodycam, dashcam should be mandatory for everyone interested in their personal safety, as the words of the common man against the words of a police officer has no value.