I am furious, how can i change my city?

my best friend was kidnapped, tortured and then killed, he was barely 18 years old and his parents saw as he was taken away, imagine the desperation of not being able to save your son! having that in your conscience for the rest of your life is the worst, my best friend was a happy and healthy guy, he was good looking and had a beautiful girlfriend, he did not do any drugs or anything, i do not understand why this happens in my country! i dont feel rage, i feel something way beyond that, its courage, rage, sorrow, confusion and fear mixed in a blender, the thought of having to raise children in a place like this makes me tremble with fear. my favorite singer was killed also his name was Valentin Elizalde and the killers have never been found! not even my best friends killers, this is outrageous, what can i do!! not even a police commander can do anything! one only lasted 2 hours in office before he got killed, please tell me what i can do to help my beautiful Tijuana city!