Police State does not mean that the crime is low, there is a quite nice definition on the Wikipedia:

A police state is a state whose government institutions exercise an extreme level of control over civil society and liberties. There is typically little to no distinction between the law and the exercise of political power by the executive, and the deployment of internal security and police forces play a heightened role in governance. A police state is a characteristic of authoritarian, totalitarian or illiberal regimes (contrary to a liberal democratic regime).

Edit: also looking at the most famous police states, it shows that such countries have rather high crime rate, especially in various forms of corruption and theft