The two major schools of thought about why crime exists, and therefore how to prevent it, are psychological and sociological. The psychological school believes that a criminal temperament grows out of childhood experiences or chemical imbalances, and therefore crime prevention should concentrate on those individuals with “criminal” tendencies. A typical connection is that child abuse causes subsequent criminal behavior. The second school maintains that social conditions -- poverty, racial prejudice, inadequate schools, etc. -- have as their natural consequence criminal behavior as an inevitable response to social injustices -- the social phenomenon. Their solutions, then, revolve around improving social conditions.
As with all over-simple views, these two views can generate both strong support examples and strong exceptions, and neither takes into account “human nature” (group superiority) or the “seven deadly sins” (greed, anger, etc.) or “anthropologic survival techniques” (dominance of species). The centuries-old philosophical truth is “People do the same thing for different reasons.”