Stungun
Much like the Weapon, the Stungun is used for handling possible aggressors and with them, possible hostages. The Stungun has some extra steps, though. Like the Weapon, the Stungun can be found in a police car. You can find it by opening the back of the vehicle.
How to use
You can both open the vehicle door and pick up the Stungun by reaching for it and pressing the trigger button of your controller. Unlike the Weapon, which can be fired after picking it up, you must unlock it first. To achieve this, simply move the joystick of your controller down. If you do not intend to use it for the time being, you can lock it again by moving the joystick up. The Stungun also has a switch on the side which indicates if it is locked or not. You can see that switch moving up or down, depending on whether you just locked or unlocked it.