Police

The police (also known as cops or pigs) are present in all Grand Theft Auto games.

The role of the Police ingame is to make crimes difficult for the player - and to provide a reliable enemy and a challenge in many missions.

In Grand Theft Auto: San Andreas, Officers Frank Tenpenny and Eddie Pulaski try to frame the protagonist Carl Johnson for the murder of another cop.

The Police work upon a system of Wanted Stars. If the player is noticed performing a crime (ranging from crashing into a Police car to holding up shops) he may gain a Wanted Star, bringing his Wanted Level to one of six. With a Wanted Level of one, any passing Cop will chase the player and attempt to arrest (or kill) him. With more serious crimes, higher Wanted Levels are issued, and different levels of Law Enforcement will join the pursuit.

If the player gets arrested by the police, there is no trial; the player loses some money and all of his weapons upon release.

What the Police Won't Arrest You For in Grand Theft Auto That Gets You Arrested in Real Life

• foul language (Carl Johnson says shit, motherfucker, fuck, etc. in public all the time and that never triggers cops to arrest him)
• trepassing private property (residential or otherwise) - it is considered compulsory in Grand Theft Auto III to collect all the hidden packages
• indecent exposure (cops don't care that Carl Johnson strips down to his briefs in Grand Theft Auto: San Andreas)
• speeding
• evading highway patrol/local cops
• resisting arrest by running away and not shooting/hitting/blowing up either police officers or civilians
• blowing up gas pumps at the gas station
• flying your airplane or helicopter too low
• using illegally-earned money to purchase a business or a house to save your game in
• jumping on other people's car and riding on top of their roofs (only works on Grand Theft Auto: San Andreas as far as I know)
• posing as a taxi driver, ambulance driver, or firefighter and doing missions