The Law of Evidence is a system of rules for the presentation of evidence in court during a trial. You can define evidence as proof, either written or unwritten of allegations at issue between parties. It is the means employed for the purpose of proving an unknown or disputed fact and includes any information upon which a person can base a decision. In summary, it is the means by which you prove or disprove an alleged matter of fact in a court of law.
Types of Evidence
(a) Real Evidence
Another term for real evidence is exhibit. An exhibit is a physical object or a document which you produce in court or show to a witness who is giving evidence and referring to it. It includes an object or document recovered at the crime scene or used by the criminal in perpetuating the offence or a product of the crime.
An exhibit must be authentic and must be identifiable visually or through any of the other senses. Authenticity is simply a demonstration that the exhibit is what it purports to be. Therefore, authentication is proving that the exhibit is what it purports to be. It must also be demonstrated that the exhibit has not changed or been altered between the events and the trial. You can authenticate real evidence in either or all of these 3 ways:
- Identification of a unique object;
- Establishing a chain of custody;
- Identification of an object that the crime or criminal has made unique.
You must recover an exhibit in a legal manner and preserve or store it in a proper manner to prevent deterioration.
(b) Demonstrative Evidence
Demonstrative evidence demonstrates or illustrates the testimony of a witness. It will be admissible when it fairly and accurately reflects that testimony and is otherwise unobjectionable. Typical examples of demonstrative evidence include videos, photographs, maps, scene sketches and diagrams. The witness who is illustrating his testimony using demonstrative evidence authenticates it.
Videos and photographs can either be real or demonstrative evidence depending on how the witness authenticates them. When a video or photograph is authenticated by a witness who observed what is depicted in it and can testify that it accurately reflects what he saw, the video or photograph is demonstrative evidence. When they authenticated by a technician or other witness who testifies about the operation of the equipment used to take them, they are real evidence and have been termed in some jurisdictions as a ‘silent witnesses.’
(c) Documentary Evidence
A document is anything you write that is capable of being evidence. It is immaterial on what the writing may be inscribed. Under the law, a document includes any publication and any matter which you write, express or describe upon any substance by means of letters, figures, or marks.
You must prove documents by primary evidence, except in certain special circumstances. Primary evidence means that you produce the document itself in its original form for the inspection of the court. Where the original document is not available, the document may be proved by secondary evidence. Secondary evidence includes certified copies and copies made from the original by mechanical processes which ensure the accuracy of the copy. You may give secondary evidence of a document in the following circumstances:
- When the original is in the possession or power of the accused person;
- When the original is in the possession or power of a person out or reach of, or not subject to the process of the court;
- When the accused person admits the contents of the document;
- When you have lost or destroyed the original;
- When the original is of such a nature as not to be easily movable;
- When the original is a public document;
- When the law permits the use of a certified copy of the original;
- When the original consists of numerous accounts or other documents which the court cannot conveniently examine and the fact to be proved is the general result of the whole collection.
(d) Oral Evidence
You may prove all facts, except contents of a document, by oral evidence. Oral evidence must be direct. Direct evidence means:
- With reference to a fact which has been seen, the evidence of a witness who says he saw it;
- With reference to a fact which could be heard, the evidence of a witness who says he heard it;
- With reference to a fact which could be perceived by any other sense or in any manner, the evidence of a witness who says he perceived it by that sense or in that manner;
- With reference to an opinion, the evidence of the person who holds that opinion.
Every person of sound mind and sufficient understanding has the competency to be a witness. Competency means adequately qualified or capable of doing something. The general rule is that all persons are qualified to be witnesses and to testify before a court of law. The tests for qualification as a witness are:
- Whether the person is prevented from understanding questions put to him; and
- Whether the person is prevented from giving rational answers to questions put to him.
The reasons why someone may not be qualified as a witness are:
- Tender years;
- Extreme old age;
- Disease of the body;
- Disease of the mind.
A mentally disordered person or a lunatic is qualified to be a witness unless his condition prevents him from understanding the questions and giving rational answers to questions. In the case of a witness who is unable to speak, the law provides that such a witness is still qualified and may give his testimony by writing in open court or using sign language in open court.
An expert witness is a person who by virtue of education, training, skill or experience has specialized knowledge in a particular subject beyond that which the average person has. Such a person can guide the court with his expertise. Specially skilled persons on whose opinion the court relies are known as experts. When a court needs to form an opinion on a specialized subject, opinions of persons specially skilled in that particular subject can be heard in court to guide the court. The court can form an opinion on any of the following subjects; foreign law, science, art, identity of handwriting, genuineness of handwriting and identity of finger or other impressions.