You could have the guy get away search for the guy. Talk to people or interregate people. Make the player have to put clues together, but also to hide and conceal themselve. Make a sript that everytime a civi see you there is a probability they will call the police.
I had an idea. Make this guy get caught up in something bigger...
They guy runs into the cop car. The cop gets out and yells at him. The player tries to explain that it was an accident. Suddenly a shot rings out from no where. You go for the gun in your car, not knowning what is happening. You look around and there is no shooter, but the cop is on the ground dead or dying. You try to help the cop. You look around and see civs. You yells out he killed a cop. They run. You try to tell they that you did not do it. Soon you hear sirens. Do a monologue to yourself about your options. Then you hear a car screech away. You decide to follow him it is your only chance to find the real killer. Then the story and clues grow from there. I have other ideas if you want to hear them. Good cutscenes are the most important part of this idea.
This could be a great short CP.