The nation of Georgia fired its entire police fore. Crime went down!

Georgian President Mikheil Saakashvili had noticed a distinct level of corruption among his countries police officers, and to be honest, he wasn't very pleased with it. In 2004, Mikheil Saakashvili threatened all police officers, whether new recruits, or seasoned veterans, that they would be instantly fired if they were caught taking bribe from citizens, or abusing their power in any way.
The cops assumed the President was bluffing, and the next day, over 15,000 cops were caught taking bribes from citizens. As promised, the President fired all of them. In the following days after that, another 15,000 cops were fired for abusing their power. The country had no police force at this point.
In fact, the country had no police force for the next 3 months! So, was there rioting and unprecedented levels of crime? Nope! As it turns out, the crime rate actually lowered, and the country was better off without cops than it was WITH cops! Apparently the cops were the reason for most of the problems and crime in the first place!
(Source)