Pretty much a given. Take a large city. Create a climate where criminals run rampant and citizens are helpless. Create a justice system that is inadequate to contain the violence and protect the citizens. Then when the citizens start to stand up for themselves, use the police to crush them. Because criminals are no threat at all to the politicians while the citizens can break them, put them in jail or out of a job if they just wake up and put their foot down. Criminals are a politicians best friend, they do what the politicians would like to have the police do if it weren't for the fact that most police officers have morals.
Decent law abiding people must fear criminals and the law while criminals have nothing to fear.