You could have a new 'commerce', a Police Station, this will work with say a Jail.
now Here is the twist..
You could have city economy statistics, Stock Market (will need a city exchange commerce of some sort) and this will go up or down depending on the amount of money you bring in from your commerces (flower shop, bowling etc).
Now if you get a mini crime wave the police are called to catch the offenders and lock them in jail, so the police station works on criminals caught, the jail works on criminals locked up. The more crimes commited in your city the more it effects the stock market of your city, more crimes = decrease in value to your stock market.
now this will also work with the Investements (alowing to invest with current friends) as your city decreases in value the investment becomes less valuable and visa versa.
What do you think?
Any other ideas to help tweak this one would be greatly appreciated as i think at some point down the line this could be a viable working idea.