Photography at crime scenes is an unsurpassed means of illustrating items of evidence, their relationship to each other, and their physical surroundings. Photography, if conducted properly, accomplishes this with great efficiency and detail. In addition to providing a pictorial documentation of the crime scene, photographs assist in the overall investigation. They are often used to support and verify testimony of witnesses and to assist in the evaluation of evidence. In some cases, photographs may be a critical factor in determining the guilt or innocence of a suspect.