Crime scene imaging techniques
By William C. Sampson
Crime scene photographs provide a permanent visual record of the crime scene as it was found, depicting what was seen and collected by the investigator, and are essential in follow-up investigations and court proceedings. This article addresses:
- Basic crime scene documentation principles and procedures
- General photographic guidelines
- Outdoor scenes
- Indoor scenes
- People who make a living through photography
- People who take photos as a hobby or pleasure
- People who use photos in their occupation for a business purpose. Crime scene photography is an adjunct to the investigator''s occupation, and the photographer does not have to be a professional.
Photographs are normally taken from the outside of a scene to the inside (core area) of the scene.
Be consistent when taking photographs. Photograph each aspect of a crime scene from distant, mid-range, and close-up perspectives.
Film is inexpensive. Take numerous photographs. Film cost does not override the value of complete and thorough photographic documentation of a crime scene.
Carry a spare camera and flash, batteries, film, tripods. Back-up equipment and proper training will allow the photographer to produce acceptable results.
Investigators should maintain a photographic log as a reference to where and what photos have been taken, as well as the conditions under which the photographs were obtained. A log also helps the photographer present a professional image when testifying in court.
The log should include:
- Identity of photographer
- Location of crime
- Type of case
- Case number or other identifying number
- Orientation, description of the scene
- Type of camera/lens used
- Type of film used
- Light source, type of strobe (manual or automatic, fill)
- Shutter speed
- Lens aperture - Because photography does have some inherent limitations, always create a crime scene sketch as an addendum to the photographic log.
- Photographs are two-dimensional and cannot show distances and measurements accurately between objects.
- Irrelevant details may be present in photographs.
- Photos can fail to show concealed details.
- Inability of single photo to show an entire crime scene. The sketch, used in conjunction with photographs, will present a clear, complete and accurate view of the crime scene. Photographs should be taken first, with the supplemental sketch created later.
- When you arrive on the scene, obtain as much information about the case as you can from the lead investigator or first-responding officer. This will provide a basic plan for taking photographs and help to determine specific photographic requirements. Take exterior photographs before the interior photographs. Obtain photos that illustrate the following:
- How the subject(s) approached, left the scene.
- How scene was entered and exited.
- How crime was committed.
- Items handled or moved.
- Interior photographs:
- Take a minimum of four photographs from each corner of the room. Options:Take photos from wall-to-wall or points of the compass.
- Use a tripod-mounted camera with a wide-angle lens set at the entry point of the room to obtain overlapping panoramic photographs. Then shoot the scene from the opposite side of the room. Option: Before entering a room, use an instant camera mounted on an extension pole to obtain overhead photographs of the scene. This allows you to locate and identify evidence hidden behind furniture or other objects.
- Take photos from eye-level perspective of the first person on the scene - whether a witness or first-responding officer.
- Eyewitness perspectives should be photographed by line-of-sight to and from the scene core. Photograph obstructions. These photographs are crucial in determining if a witness, subject or officer''s line-of-sight of an object was clear or obstructed.
- If practical, have two photographers record the crime scene to obtain different perspectives. This also reduces the likelihood of inadvertent destruction or damage to film, lost film, and equipment malfunction. Or, have one photographer shoot 35mm film while the other takes instant photos as back-up documentation.
- If an object or piece of evidence is obstructed, a minimum of two photographs should be taken. One photo with the obstruction in place and the second after its removal.
- When taking instant photos, attach a label to the back of each image identifying the investigator/photographer, date, type of case and case number.
- With 35mm film, write the above information on a piece of gray card or similar device and photograph it at the beginning of each roll. Also, sequentially number each roll of film used, e.g. "roll 1 of 8," "roll 2 of 8," etc. Immediately photograph evidence that may be contaminated, inadvertently destroyed or damaged by inclement weather conditions.
- Long-range photographs could include aerial or overhead photographs, exterior, interior or any photographs that encompass a wide portion of the scene. These photographs identify the location of the crime.
- Mid-range photographs are approximately ten to twenty feet from the subject matter. Care should be taken that the photographs can be easily compared with the long-range photos. Mid-range photography provides an orientation of an object within a scene.
- Close-up photographs are taken from distance of approximately five feet or less. The close-up photos should depict items that could not be adequately seen from the two previous ranges. Photographs show the relationship of evidence to the scene, and ultimately illustrate a connection to be made between the scene and defendant, and also help to establish the chain of custody.
- Macro photography with and without scale may be used to record tool marks or fracture patterns. This may be as close as a few inches. Always use a scale when taking photographs to show distance and size relationships. Each item should be photographed with and without a scale in the event the use of a scale in a photo is ruled prejudicial.
- Photograph the scene as it is found. This is a general rule that applies to all scenes. Do not reconstruct the scene by placing objects that may have been inadvertently moved back into the scene. If an item or object has been moved prior to photographing the scene, photograph it in its new location. Next place the object in its original position and photograph it again. This action should be noted in the photo log and/or on the sketch.
Outdoor crime scenes:
- Outdoor scenes change constantly. Lack of security or inadvertent destruction of evidence by well-meaning investigators or unauthorized personnel can effect the outcome of a case.
- Weather conditions can destroy fragile evidence. Protect crucial evidence with a portable shelter like a tent or canopy.
- Approaching the crime scene may also destroy valuable evidence. Carefully observe routes for approach and entry to scene. Avoid making footwear impressions, etc.
- Crowds may also be present at a scene. Take photographs of the crowd. One of the onlookers may be the perpetrator of the crime or witness to the incident.
- Photographs of outdoor crime scenes, or the approaches to an indoor scene should include a landmark as a point of reference. For example, street signs at intersections are excellent reference points.
- Use long distance, mid-distance and close up photographs to record the scene and items of evidence.
- Record house numbers and exterior of house or building.
- Photograph paths leading to and from scene.
Photograph shoe and tire impressions with and without a scale using instant or 35mm color film, or black and white for additional contrast.
Utilize two cameras, each loaded with a different type of film, photographing from the same perspective. Both cameras should be set perpendicular to the surface being photographed, using a heavy-duty tripod with a dual-head support.
The camera(s) should be set at a constant height to fill the frame with as much of the impression as possible. A distance of 30 to 38 inches from camera lens to the impression is acceptable. Photograph from the same perspective with each camera.
Use a scale to indicate size. Commercial rules designed specifically for footwear or tire impressions are desirable. Place the scale parallel to, and on the same plane as, the impression.
- Impressions can be photographed with side lighting or oblique lighting as follows:
- Set flash at 20 to 45 degree angle to subject.
- Use flashlight to determine the best angle and shadowing effect to produce the greatest contrast in the impression.
- Option 1 - Use flash from right side of impression to left side of impression, from left side of impression to right side, from rear of impression to front of impression, and front to rear.
- Option 2 - Use the flash crossing the impression with an "X" pattern.
- Option 3 - Use the flash from clock coordinates.
- Suggestion: If there is too much sunlight, shroud the impression and use the flash to highlight the impressions in the same manner as the previous description.
Interior scene photography uses the same basic techniques described in the general photography techniques and introduction sections of this document.
- Indoor scenes are photographed with available light; incandescent light; fluorescent light; electronic flash, or a combination of these light sources.
- During a trial, an investigator may be asked if a photograph accurately depicts the scene as found. Be prepared to discuss the lighting technique used, and why you selected it.
- Most indoor photography can be done using a normal lens. A wide-angle lens can be used to obtain an overall view of the interior.
- Photographer, investigator, bystanders should not appear in any scene photographs.
- Avoid scrapbook-type photos or jocular poses by officers on the scene.
- Photographs provide the jury with a visual record of scene and evidence as it was found, and must illustrate key points clearly without verbal support.
- Photograph blood evidence and note the time the first photograph was taken. Re-take photos every hour, recording the time and air temperature when each image is taken.
- All fingerprint or footwear evidence should be documented. Record and document heights/location of latent print evidence on porous walls. Fingerprints, which may be destroyed in the collection process, should be recorded and photographed before processing. Oblique lighting with a flashlight may be used in lieu of an electronic flash unit.
- If a Polaroid Spectra Law Enforcement Kit is used, take photos using the 1:1 copystand attachment. Place the system directly over the developed fingerprint when taking the photograph. Also, mount the camera on a tripod and use the system''s close-up lens attachment to obtain photos.
- Take photos with and without a scale.
- Mid-range documentation should be made for orientation purposes, illustrating where the latent fingerprint evidence was located.
Unfortunately, most cases involving motor vehicles are seen as routine in nature, and proper techniques are often not followed.
- Photograph vehicle from front, back, left side, right side. Using a camera mounted on an extension pole, photograph the top of the vehicle, including roof, hood and trunk areas.
- Photograph license plate and registration decal from mid-range and close-up perspectives.
- Photograph the VIN number using a macro lens.
- Examine, photograph vehicle undercarriage.
- Photograph damage and trace evidence collected.
- Obtain mid-range and close-up photos of damaged areas showing possible identifying fracture patterns or tool mark evidence.
- Obtain photos with and without a scale. Evidence found in the vehicle should be photographed with and without an alpha or numeric identifier. A photographic log sheet should be made showing locations where evidence is found. Create a sketch of upper and lower quadrants of vehicle interior. Note areas on the sketch where photographs are taken and items of evidential value are found.
- The object pictured must be relevant to the issue.
- The photograph must not appeal to the emotions, or prejudice the court or the jury. The photograph must be free from distortion and not misrepresent the scene or object it purports to represent. A photograph taken using the proper techniques and procedures, if properly exposed; taken at the correct angle; and depicting the scene accurately, may become key evidence in a criminal case. In fact, in some instances, photographs may reveal evidence previously overlooked at a crime scene.