I agree it is not murder even if it was a break with policy, regardless of when the policy was enacted. Every police officer in that district ought to strike. They ought to just not show up for a week in protest of that one. Mobs of thieves and vandals are not the only ones who can protest.
That is difficult though. These people need their income, they have bills to pay. taking such an action could result in their being fired.
Personally, I don’t see how a person becomes a policeman at this point. You expect that people in higher positions of authority will act prudently as opposed to feeding you to a mob of lunatics.
That didn’t happen here. This is bad, and it has the potential to get much worse.