A crime film, in its most general sense, is a film that deals with crime, criminal justice and the darker side of human nature. Stylistically, it can fall under many different genres, most commonly drama, thriller, mystery and film noir. Films focused on the Mafia are a typical example of crime films.

 

Adaptation

 

Crime films have been generally adapted from other forms of literature rather than written directly for the screen. What's seen as the bleak nature of some of these source materials often led some in the film industry to attempt to "lighten" the story when it was translated into film. Goodfellas is an example.

 

Gangster films typically focus on the power struggles within gangs rather than on the policemen who try to stop them (although there are exceptions, such as The Untouchables). The most common storyline depicts an individual's rise to power within the organization, followed by his betrayal and murder by the gang or being killed by police. This story offers a moral message against crime, while also permitting the audience to vicariously enjoy the gangster's exploits.

 

Several famous examples of changing with the plot exist. One of them is Alfred Hitchcock's (1899 - 1980) film Suspicion (U.S., 1941), which is based on Francis Iles's novel Before the Fact (1932). Alterations of the plot are often due to external factors such as a particular actor's previous roles. While director Howard Hawks was filming The Big Sleep (1946), a classic example of film noir, Humphrey Bogart and his leading lady, Lauren Bacall, got married, which resulted in the studio exploiting -- and cashing in on -- their off-screen relationship by adding several scenes featuring the couple which are not based on Chandler's novel.

 

When the best-selling novel The Godfather was adapted for film, much of the dark elements were kept intact, while lighter subplots (about an alcoholic singer and a Las Vegas doctor who performs a vaginal reconstruction) are left out.

 

There are also straightforward adaptations of crime and mystery novels. Sir Peter Ustinov is seen by many as the definitive Hercule Poirot in several films based on Agatha Christie's novels such as Death on the Nile, Evil Under the Sun, and Dead Man's Folly.