When they find a fingerprint at a crime scene, they can easily match it to fingerprints on their computers. As a result, it is much easier to identify criminals. These days, however, police can also identify criminals through DNA.
DNA is information carried in our bodies. DNA is responsible for the colour of our hair, the colour of our eyes and everything else about us. Just as no two people have the same fingerprints, no two people have the same DNA.