tire tracks can also be especially useful.
Every tire has an easy- to-see-tread,
a pattern of lines in the rubber.
Even without special equipment, police can often see this pattern in mud, o grass,
or even on the surface of a hard road near a crime scene.
A case in the state of Minnesota is a good example.
The police tried for four years to find a criminal who had set several forest fires.Then they found an old tire track,obviously from a truck, at the edge of a burned-out forest.An officer took a picture and tried to match the tread pattern to the tires of trucks he saw around town. Finally,he found a perfect match, and the truck's owner confessed to starting the fires.