In law, direct evidence is that which proves or disproves innocence without requiring inference on the part of the judge or jury. There are several different types of direct evidence, including witness testimony, audio or video recordings, and documentation. Some forms of evidence, such as DNA samples, may be considered direct evidence only in certain cases.
Eyewitness testimony is one of the most common types of direct evidence. If a witness sees or hears a criminal act, he can relate the events to the best of his ability. In general, courts assume that a witness is an objective party who can be relied upon to relate the events as they happened, without requiring the court to make an inference as to what happened. Visual testimony from a witness, such as watching the defendant shoot a victim, is usually considered the most reliable form of direct evidence. If a witness only hears a gunshot, he or she cannot directly testify as to who shot the gun, and therefore may be giving circumstantial, rather than direct, evidence.
Though witness testimony is one of the most frequently used types of direct evidence, it is not always fully reliable. Witnesses may have biases that can affect their testimony, or may have difficulty remembering the exact sequence of events due to stress or shock. Judges and juries must determine the reliability and objectivity of the witness when considering how to weigh direct evidence from an eyewitness.
More reliable forms of direct evidence include audio and video recordings. Since a tape recorder or video camera cannot have a bias, the objectivity of this type of evidence is usually unquestionable. Surveillance tapes, wiretap recordings, and even cell phone recordings can all serve as a direct form of objective evidence that establishes what actually happened during a crime. In some cases, however, recordings may be inadmissible as evidence if they are obtained illegally; for instance, in California, it is sometimes illegal to make a recording of a person without his or her knowledge. In order to make sure that recordings can be used, lawyers and legal officials must take care to follow all applicable laws of evidence gathering.
Documentation used as direct evidence might include emails, letters, or diary entries. These are generally only considered direct if they contain the actual crime, such as an email that includes death threats. If a perpetrator confesses his or her crimes via written correspondence, or a witness details an account of a crime in writing, it may also be considered a form of factual evidence.
In paternity cases, DNA evidence can serve as a form of direct, factual evidence. DNA is widely considered a reliable method of establishing paternity, and thus does not merely infer that a child is related by blood to a father or mother, but serves as objective proof of the fact. In many criminal cases, however, DNA evidence such as fingerprints or blood matches, is considered circumstantial. While it may prove that a person was present at a crime scene, it does not objectively show whether or not the person in question committed a crime.