In prehistoric times, detectives and crime scene investigators at a crime scene recorded their findings by writing down notes in a notepad using a pen and paper.
Remember those?
Nowadays, it is common to see those investigators using electronic devises such as IPads, cellphones and other digital tools of the trade to take those same “notes.”
So, does the correct four-prong crime scene investigation procedure of videography, then still photography, then sketching and then evidence collection still require the sketching?
Yes, because an investigator must still record exact dimensions, and it is these crucial sketch dimensions that can be later explained and clarified using still photographs and video to a jury. Crime scene investigation cannot round up or round down inches, feet or yards to be accurate . . . it must be exact. Forensic science is just that . . . a science.
While at the crime scene, an investigator only has to prepare what is referred to as a “rough sketch” because it doesn’t need to look pretty – but the dimensions must be exact. I have done many a rough sketch at a crime scene while standing in a burnt-out home still acrid and smoldering; out in the freezing cold during a fatal motor vehicle accident on a snowy night; and at homicides where there are bodies, bullet casings and ligatures lying all over the floor.
A rough sketch should always be what is referred to as a “bird’s eye view” which means the view is from overhead of the crime scene. A crime scene sketch should not be in three dimension. It should resemble an architectural drawing. The aspect of two or three dimensional is covered by still photographs and video, not the sketch.
Rough Sketch
The rough sketch is prepared by the investigator at the scene, but not until AFTER all still photography and videography has been completed and BEFORE any evidence has been collected. The rough sketch does not have to be drawn to scale but should include exact measurements of the surroundings and the location of evidence in relation to the victim’s location, or other important evidence.
Necessary Materials for a Rough Sketch
The only materials necessary for the rough sketch are a lead pencil, a straightedge, and a pad of paper. Graph paper is recommended since it will provide a scale and a guide for the line to be drawn. A magnetic compass is also a useful device in establishing a permanent directional reference, because the sketch must depict true north. The most convenient scale for sketches produced on 8.5″ x 11″ paper is 1/4″ = 1 ft. as this is the scale used on drawing templates.
Measurements for a Rough Sketch
All measurements recorded at the scene must be accurate. If the scene is a large area, a sufficient degree of accuracy may be obtained using yards or tenths of a mile, but it may be necessary to measure smaller areas to within one sixteenth of an inch. It is always preferable to work with an assistant when possible and have them verify all measurements before they are recorded. Note: Measurements of the location of moveable objects should refer to at least two fixed objects such as doors and windows. In doing so, the moveable objects can be relocated in their original position later.
Two methods are generally employed for locating objects within an area. First is the coordinate method: distances are shown by two mutually perpendicular lines. It the scene is a room, the objects of interest are mapped with lines drawn to the nearest wall as shown in the illustration to the right. The second method of measurement is triangulation which is most often applied to scenes within large buildings such as a warehouse, factory or outdoor scenes.
To triangulate, select two fixed objects such as structural supports, doorways, windows, stairways, trees or nearby buildings. In an outdoor scene, utility poles and/or traffic signs can also be used, however over time they may be damaged or removed by traffic accidents.
Development and Use of a Legend
To reduce the amount of artistic skill and produce a simple rough sketch, a system of symbols should be employed to identify various objects. These symbols are then defined in the legend. In sketches of relatively large areas, conventional signs and symbols may be used. If it is necessary to depict considerable detail within a small area, these various objects maybe indicated with letters and/or numbers and keyed to the legend.
Preparing the Rough Sketch
The best starting point for filling in the details of the crime scene is an entranceway. Begin the sketch from the investigator’s left and fill in the details in a clockwise fashion. Place all windows and doors, then plot the positions of furniture. The final task is to record the location of all physical evidence and assign each piece a letter or number that is keyed to the legend. If anything has been moved by the investigators, victims, or witnesses, ensure the items are returned to their original position before placing them on the sketch.
1. Record the dimensions of the room or area in questions.
2. Locate all fixed objects such as doors, windows, light fixtures, closets, etc.
3. Finally, locate all moveable objects starting with furniture and ending with items to be used as evidence.
With the completion of the rough sketch, the investigator is now free to collect and secure the evidence. Never add or delete anything on the sketch after leaving the scene and place only important items on it–never trust your recollection. When this task is complete, the next step is to return to their office and prepare the finished sketch, which can be done either freehand or using computer software. It is generally legally accepted that the rough sketch be retained as part of the investigator’s work product.
Finished Sketch
The purpose of the finished sketch is to give the investigator a clear picture of the crime scene. The finished sketch is a duplicate of the rough sketch prepared to scale by using layout templates and exact distances. Reminder: The most convenient scale for sketches produced on 8.5″ x 11″ paper is 1/4″ = 1 ft. The basic tools required are a transparent ruler, pencils, paper, triangles (30, 60 and 45 degree), architect’s template and building interior template.
Titling Crime Scene Sketches
Each crime scene sketch must be identified in such a way as to preclude confusion and misrepresentation. Establish a format and use it consistently on all sketches. The title should include the case identification number, location of the incident, type of offense, date, time, and the name of the investigator and the assistants at the scene. All this data serves to authenticate the sketch and further establishes the credibility of the investigator. The crime scene sketch is just as important as the evidence collected at the scene. After all, without it, much of the evidence will have little relevancy if it cannot be pinpointed to a position within the crime scene. It is not necessary to depict paintings on the walls, mirrors, etc. as these will be covered in still photography and/or video.
So even in this digital age, it is still proper and necessary to follow the correct method of documenting crime scenes. Otherwise, when it comes time for the criminal trial, the jury might feel that crime scene investigation performed by the investigators was . . . sketchy.
Ouch.
