Direct versus Circumstantial Evidence
Evidence can be either direct or circumstantial. Direct evidence establishes a fact. Examples of direct evidence are eyewitness statements and confessions. Circumstantial evidence, on the other hand, requires that a judge and/or jury make an indirect judgment, or inference, about what happened.
For example, if a fingerprint or hair found at the crime scene matches that of a suspect, jurors may infer that the print or hair is indeed that of the defendant, and because it was found at the crime scene, links the defendant to the scene.
Circumstantial evidence is not absolute proof; instead, it provides a general idea of what happened. Most often, evidence identified through forensic science is circumstantial, though direct evidence such as witness and victim statements or suspect confessions may impact the ME’s interpretation of test results or his reconstruction of the crime scene.
Circumstantial evidence often is much more reliable than direct evidence. Eyewitnesses are notoriously bad at identifying suspects or recalling events. After all, people tend to interpret what happened instead of simply playing it back like a film loop.
Furthermore, circumstantial evidence is more objective and is more likely to provide a reliable answer. An eyewitness may be wrong as much as half the time, but fingerprints and DNA evidence can, more often than not, accurately distinguish the individual in question from the other 7 billion people on Earth.