So someone steals your car at gunpoint. You report it to the cops, who take a report and otherwise do nothing.
You and your friends then find your car. You attempt to retrieve it, but knowing that the thieves are armed, you make sure that you are, too. The thieves then produce weapons in furtherance of their crime. You shoot them in self defense.
The cops THEN decide to do something and arrest you for murder because you did the job that they are being paid to do, but don’t.
Now you are in court, and I somehow have made it on to the jury. I will vote not guilty, and if it were in my power, I would vote to have the government take the cost of your defense out of the pension fund of the local cops.