If you do not want to try and find the random person in the crowd after firing your gun, or look for Blume affiliates, there is another method you can use that will allow you to always know who is going to call the cops.
Carjacking. They do not always call the cops, but most of the time they will. Simply steal someone's car, and then watch them closely, if they call the cops, run up to them and take their phone, or use jam coms.
Rinse and repeat and this will easily be yours. Obviously there has to be someone in the car, so taking empty rides from parking lots isn't going to work.
I hope this helps people who want to take a little bit of the random factor out of this. Please feel free to comment if you need more clarification.