Physical evidence comes in all shapes and sizes, and there are multiple search patterns that are used to identify evidence. These patterns include line/strip search (used by one or two investigators who walk in straight lines across the crime scene) this method is best used in scenes where the boundaries are well established because the boundaries dictate the beginning and end of the search lines, grid search (two or more people who perform overlapping line searches forming a grid) is best used when boundaries are well established, spiral search (investigator moves in an inward spiral from the boundary to the center of the scene or in an outward spiral from the center to the boundary of a scene) is good when the searcher is moving from an area light in evidence to an area that has more evidence, wheel/ray search (several people move from the boundary straight toward the center of the scene (inward) or from the center straight to the boundary (outward)) is not preferred because areas in-between are not being searched, and quadrant/zone search (the crime scene is divided into smaller sections (zones or quadrants) and team members are assigned to search each section; each of these sections can be subdivided into smaller sections for smaller teams to search thoroughly) is best for large areas.
Notes, photographs and sketches are the three methods for crime-scene recording. The notes should start by identifying the person who contacted the investigator, the time of the contact, and any preliminary information disclosed, including the case number. When the lead investigator arrives, the note-taker should record the date and time of arrival, which is present, and the identities of any other personnel who are being contacted. If others are being contacted their names, titles, and times of arrival should be recorded as well. Before the scene is sketched, photographed, or searched, the lead investigator carries out the initial walk-through. During this walk-through, the investigator should take notes on many aspects of the crime scene in its original condition. Tape recording notes at a scene can be advantageous because
detailed notes can be taped much faster than they can be written. At some point, however, the tape must be transported into a written document. Photographs are commonly accepted in most jurisdictions as visual evidence in criminal investigations.
The goal of photography is to produce examination-quality photographs. Meaning that everyone involved, from the investigators to the judge must be able to interpret the photographs easily. Photography is also important for documenting biological evidence in its original condition, because this type of evidence is often altered during testing. Certain parts of the scene must be photographed such as the layout of the scene, the position of evidence to be collected, and the relation of objects at the scene to one another. Photographs cannot stand alone; they are complementary to notes and sketches. Once the investigator has taken sufficient notes and photographs, he or she sketches the scene. The sketch serves many important functions in the legal investigation of a crime. If done correctly, a sketch can clearly show the layout of an indoor or outdoor crime scene and the relationship in space of all the items and features significant to the investigation. All sketches must include certain features. The title block contains the case number, the agency number, the name and title of the artist, the location of the scene, and the date and time at which the sketch was created.
The legend should contain the key to the identity and dimensions of the objects or evidence and may be represented by symbols, letters, or numbers. The compass should show an arrow to denote north in relation to the scene. The body of the sketch contains the drawing itself and all dimensions and objects located within it. Sketches are especially important to illustrate the location of collected evidence. Measurements over long distances and the topography of our door scenes can be shown in sketches. Paths of entry, exit, and movement through the scene may be speculated from a good sketch. A sketch can help demonstrate if a witness’s testimony is feasible or not. To be effective, a sketch must be clear enough to be used in reconstruction by other investigative personnel and to illustrate aspects of the crime scene to a jury. Finished sketches can be carefully made by hand or by using a computer-aided drafting program.
(Saferstein, Richard 2009). Forensic science: From the crime scene to the crime lab. New Jersey: Pearson.