Its pretty open and shut really - I know the idea is to prove it with overwhelming english literary skills, but the more people there are, the more crime/violence there will be, BECAUSE there are more people to cause the violence. Sounds a pretty silly question to me. Its like saying, the more jobs become available, the more populous the city will become - obviously, because more jobs mean more people. And just the same, more people means more people to cause crime. I would just write "The answer is in the question, it is obvious that in a village of 10 occupants there will be x amount of crime. In a town of 1000 people there will be an exponentially proportionate amount of x crime. In a city of 1 million - yadda yadda yadda"
That argument doesn't lend any weight if you consider crime in percentages of populus, which is probably what the question is getting at.
Although the question seems a bit vague - as was said previously, crime in singapore is low. Good point, depending on the culture/country crime rates, types of crime, punishment for the crime, even the very definition of a crime itself vary extremely in cities. Colombian cities, Indian cities, Chinese cities, eastern block cities, african cities all hav their own idiosynchicies.
Poverty, government legislation, religion, etc will all play their part.
