Which type of evidence shows that two objects have come into contact?

Trace evidence is the type of evidence that demonstrates a physical connection between two objects through the presence of small materials or substances. This includes fibers, hair, soil, and gunshot residue, among others. When trace evidence is analyzed, it can reveal that two items have interacted or been in close proximity to each other, indicating a possible transfer of materials. For example, if a suspect's clothing fibers are found at a crime scene, this trace evidence can support the notion that the suspect was present at that location, thereby establishing a link between them and the scene.

Other types of evidence, such as expert witness evidence, circumstantial evidence, and documentary evidence, do not specifically demonstrate direct physical contact between objects in the same way that trace evidence does. Expert witness evidence relies on the testimony and interpretation of specialists, circumstantial evidence often supports conclusions through indirect connections rather than direct physical proof, and documentary evidence consists of official records or documents, which may not provide insight into physical interactions between objects.