This is what links a suspect with a crime. Examples would be finding the suspect's fingerprints, hair, or blood at the scene. For instance, finding the person's shoe prints on the premises. It is not as definitive as a fingerprint still suggests the suspect may have been involved. It is simply evidence established by law.
Trace evidence is extremely small items, such as hair and fibers.
Sometimes it may be difficult to ascertain what is evidence and what is not. To demonstrate, at a burglary scene, a pried open window and missing items are noteworthy. A total mess could suggest searching, while a clean scene could suggest that the suspect knew exactly what to look for and where. A messy scene could also suggest that the offender was hurrying. To find out which, rely on the other evidence.