Cops 'n Crooks is a multiplayer game in Grand Theft Auto IV.
Cops 'n Crooks involves players being split into 2 teams: The Crooks, or the criminals and the Cops, or the police. The crook players are attempting to escort their boss (or themselves) to safety whilst evading the cop players, who are trying to kill them. There are two modes: One for All and All for One.
All for One
Map indicating dependency between spawn locations and getaway locations (source)
In the All for One version, the boss must attempt to escape to the getaway vehicle with aid from the crooks. The cops must attempt to kill the Boss or destroy the escape vehicle. The crooks hold no importance when escaping, therefore, there is no need for them to escape with the boss. The Boss must stay seated in the getaway vehicle for approximately 8-10 seconds.
In all for one, the crooks may choose to generate a certain amount of money until they depart; this is done by taking out cops which give $100 per kill and can be done an infinite amount of times until all the cops leave. If the Boss manages to escape, the crook team will gain $1000. Cops can also gain $1000 by taking the boss down, although, many people prefer to accumulate more money by taking down the crooks which can also be done an infinite number of times until they leave the game unexpectedly, the boss is the only one who will not respawn. When the boss dies by any means the round will automatically finish within 3-5 seconds, athough dying without being killed may result in "-$100". You may get extra cash by collecting cash dropped by the cops and the crooks when they are killed.
One for All
The One for All version has no Boss to escort, simply the Crooks keeping themselves alive and attempting to fill a getaway vehicle with teammates to win, either a boat or a helicopter. Only 4 Crooks can escape in the getaway vehicle. Once the getaway vehicle is full or all the remaining Crooks are in, they must stay seated for 8-10 seconds so the round can end. Any remaining Crooks members can either stay behind and fend off Cops or run like a renegade to stay alive until the round ends!
The Cops players win by killing all of the Crooks before they can escape. Crooks can also win by killing all the Cops. Each opponent you kill is worth $100 for your team. Killing all of the opposing team is worth another $1,000! Each Crook that escapes in the designated vehicle is worth $250, meaning a full 4-seater boat/chopper is worth $1,000. Dying on your own, like a long fall or blowing yourself up will cost your team $100, just like in All for One.
Players can NOT respawn in this mode. Once a player dies, they have to wait for the round to end.