How does crime work in your world?

I've been thinking about this recently (mostly because one of my main characters a lawyer) but how *does* crime work in your worlds?

What motivates people to break the law? Is it just something people do out of desparation? A perceived injustice? Is there some kind of organized crime ring calling the shots?

Do the same laws apply to everyone or is there specific laws for each species / fantasy race inhabiting the same space? Are there laws that only apply on specific holidays?

Once the law is broken, what happens to the offender? Is there a policing force that tracks them down, is there some force that makes them turn themselves in, or does it work more *à la* Roman Republic where the victim needs to do those things?

Once "caught" are they innocent until proven guilty? Or guilty until proven innocent? Do they get a chance to defend themselves? If there's a trial of some sort, does it happen immediately, are they normally free until it happens, or are they normally held behind bars? And who conducts the trial?