Nowadays, most of us treat police as plural and would both say and write the police were called, but anyone my age was taught as already mentioned that it is a collective noun and that one should say and write "the police was called".
It is illogical, but I think we have to accept that "police" and some other collective nouns are being treated as plural these days, while others are not.
I myself would tend to say the police were called, but that a flock of sheep was in the road!
Like others who have commented, I would usually regard incident as a noun, and cannot think when I last used it as an adjective or incidence, which is always a noun, either for that matter.