Something like this happened in Montreal couple of years ago , cops entered a home illegally and the guy shoot at one of them thinking it was intruders , his family was with him.The guy in question was known in the community and owned a inside golf course or something , and he won in court , which was surprising with the way cops always seem to come out on top in these situation.
There is more to that. The police arrived in camouflaged cars, with no uniforms. The reason is that it was Laval police who came to arrest this guy in Longueuil, so they were outside their jurisdiction and didn't wanted to be sniffed by the local police.
The man also immediately surrendered when the police announced themselves. He was entirely in his right to defend himself against a bunch of armed people who raided his house. Not so once he knew they were police.