Crime tends to fascinate viewers. Because of this, the genre of crime film has become very popular and lucrative. These movies focus on criminals, as well as the police who are attempting to capture them. Older Hollywood films would usually end with the criminal being punished. This was because there was a code of practice in place which forced movies to have a specific morality in its storytelling.
However, modern crime films have a greater degree of freedom. They can end with the criminal getting away and prospering thanks to their bad deeds. Despite this, the best movies of this genre still tend to end with the main character having to pay for their crimes.
The mafia and other forms of organized crime are often seen in this genre. A good example of this is the modern classic, The Godfather. In fact, news sites such as the Guardian consider this the greatest film ever made. In recent years movies focusing on real-life serial killers have also gained a large audience. This is likely due to society, in general, taking a greater interest in the subject of true crime.