Without exposing themselves to a high-risk situation, police officers can use DNA Bullets to mark offenders and make future arrests.
The SelectaDNA High Velocity DNA Tagging System is a pistol that shoots out little green pellets that are full of synthetic DNA. The bullets splatter a giant ink stain on the skin, marking people and leaving behind a specific code of DNA that cannot be replicated without knowledge of the original 'Key Codes.' This kind of tagging system is especially useful when there are mobs of violent people and it becomes dangerous for police to make arrests on the spot.
Once arrests are finally made, it is next to impossible to refute the marks left behind by the DNA Bullets.
DNA Bullets Allow Cops to Mark Offenders from a Safe Distance
References: selectadna & ohgizmo