When a Taser gun is deployed, two probes are fired up to 10.6 metres, attaching to the body through up to 5cm of clothing and creating an electrical circuit between the gun and the victim’s muscles and nerves.Normal gun manufacturers use various techniques to make every barrel unique. When a bullet passes through the barrel, it produces individual markings and these can be used to analyse whether the bullet was fired from a particular gun. But, unlike regular gun bullets, the Taser probes are not able to leave an identifying mark that would lead investigators back to the person that fired them.
So in 1993 the AFID system was created. Now, when many Taser guns are fired, they disperse dozens of colourful anti-felon identification (AFID) tags, which resemble confetti and are printed with tiny serial numbers. It would be very time-consuming to pick all the tags up and so inevitably the police are able to find some and trace the gun that was used.
Huge swathes of law enforcement officers also carry this variety of Taser, which helps in determining overall accountability when the gun is used in the line of duty, although it’s mainly used to trace personal Taser use.
"What it is doing is preventing people from doing crimes," says Taser Vice President Steve Tuttle. "It tells the owner, if you do, you're putting twenty to thirty [business cards] out there."