"claim the officers "should have" known at the time," 

And there it is. You claim police powers beyond what any other citizen has to grant to them. Pray thee tell then where their power and authority come from?

I don't care what they knew, they have an obligation to give EVERYONE the benefit of the doubt! Same as every other citizen. How can you call paranoid murder "public service?" Have we all become mentally ill? Seriously.

Where do you draw the line? By your logic they could shoot anybody anytime and it would be justified. A slippery blue slope called oppression. It will ruin this nation mark my words.