Grand Theft Auto 3

Vigilante missions involve tracking down criminals that are driving around the city and killing them. The mission can only be triggered when inside a law enforcement vehicle, such as a cop car, by pressing . You will then have a time limit to track down the criminal represented by the blip on the minimap and kill them. You can either ram them until they flee their vehicle or you can perform a drive-by with a sub-machine gun to destroy their vehicle. 

Unlike the Ambulance missions there aren’t any levels associated with the Vigilante missions. Once you kill the criminal on the minimap another one will appear. They don’t get any harder besides sometimes being in a bigger car, such as a Patriot. The biggest challenge is not getting your vehicle destroyed. Remember that you need to kill 20 criminals in a single vigilante mission in all three islands for the 100% completion trophy.

Below is a list of different methods to unlock this trophy, feel free to use whichever one works best for you.

Method 1: Cop car

The hardest method to obtain this trophy is to use a cop car. You can either ram or shoot the criminal vehicles to destroy them. This can take quite some time and you are likely to run out of time, or destroy your own vehicle in the process. This can be made easier with the use of the health cheat which will completely restore your car health. The weapon cheat will give you more ammunition for your sub-machine gun as well.

Method 2: Tank

The tank can be acquired either through cheats or from Phil’s armoury in Staunton Island. All you need to do is blow the criminals car up either by shooting it or driving over it. The tank can be quite slow so you are likely to run out of time.

Method 3: Pause exploit

By far the easiest of the three methods, this one uses an exploit to make killing each criminal a lot easier. When you get close to the criminals vehicle, simply press the  to pause the game and once you continue the criminal will stop and then exit his vehicle. At this point run over him in your car to kill him.

The below video shows a walkthrough of the trophy using the third method listed above.