Edward M. Robinson

Integrated DNA and fingerprint analyses in the identification of 60-year-old mummified human remains discovered in an Alaskan glacier.

Abstract:  This report describes the identification of a merchant mariner who perished in 1948 when Northwest Airlines Flight 4422, a DC‐4 carrying 24 seamen and six crew members crashed into Mount Sanford, Alaska. Fifty‐one years later, a human forearm and hand were found close by the wreckage of the plane, prompting identification efforts using DNA and fingerprints. There were significant challenges to both the fingerprint and DNA analyses. The hand was badly desiccated, making fingerprint friction‐ridge detail almost invisible and the remains had been embalmed upon discovery, making DNA amplification difficult. We present the results of an interdisciplinary approach that successfully addressed these challenges and ultimately led to the identification of the remains. These efforts relied on efficient fingerprint rejuvenation and imaging techniques that improved print resolution, as well as new DNA extraction techniques optimized for aggressively embalmed remains.

Ultraviolet, Infrared, and Fluorescence

The light that is the foundation of photography is related to the electromagnetic spectrum. This spectrum depicts light as a wave of radiation, which has a peak height (amplitude), a distance between peaks (wavelength) and a number of complete waves passing a point each second (frequency). When light strikes various surfaces, it can interact with those surfaces differently, and crime scene photographers can use these differences to visualize otherwise “invisible” evidence. Ultraviolet (UV) light can be used to search for faint blood stains, tracks, or trails. UV light can also cause nonblood body fluids, some fibers, and some fingerprints to fluoresce. The evidence can then be photographed while fluorescing and collected. Infrared (IR) light can also react differently to different substances and substrates, making it possible to visualize various types of evidence not noticed in the visible light range. Inks with different chemical makeup can frequently be distinguished, and gunshot residues on dark fabrics can more easily be seen. Printing or writing on charred documents can sometimes be visualized by the use of IR lighting techniques. Some inks can be made to fluoresce in the IR range when stimulated with blue–green light. Many types of evidence can be made to fluoresce in the visible light range of the electromagnetic spectrum, enabling the evidence to be seen, photographed, and then collected.

Focus, Depth of Field, and Lenses

When a layman speaks about wanting a camera with good resolution so that the images produced by it are clear and sharp, that person is usually oblivious to the precise meanings of such terms as “resolution,” “acutance,” and “sharpness.” This chapter explains each of these terms. It discusses and explains the methods that can be used to focus on areas rather than on individual objects. It defines depth of field and the factors that affect it. It distinguishes between different lens types and presents the effects of each lens type. It also provides suggestions on how to minimize the diffraction effect that can adversely affect the most critical images. Camera resolution is the ability of the camera system, which includes the lens optics, camera sensor (film or a digital sensor), and image-processing software, to distinguish, or “resolve” groups of alternating line pairs as the lines become increasingly thinner and they become increasingly closer together. Acutance refers to the cameras ability to render a sharp edge of the subject as a sharp edge in the photograph. There are three camera variables that directly affect the depth of field range that includes F/stop choice, lens choice, and camera-to-subject distance.

Legal Issues Related to Photographs and Digital Images

Digital images are constantly being accepted into court cases as evidence. “Processed” digital images are also being accepted into court as valid types of evidence. Qualified experts are ready to put their integrity on the line and testify that no improprieties have been used to produce the images being offered as evidence in court. These photographs have certain standards by which they will be evaluated. They have to fairly and accurately represent the scene as it was originally found. They have to be authentic. They have to be relevant and material, just like any other evidence introduced in the course of the trial. And they cannot unduly bias the juror against either subject in the proceeding, by inflaming the emotions of the juror.

Chapter 5 – Focus, Depth of Field, and Lenses

When a layman speaks about wanting a camera with good resolution so that the images produced by it are clear and sharp, that person is usually oblivious to the precise meanings of such terms as “resolution,” “acutance,” and “sharpness.” This chapter explains each of these terms. It discusses and explains the methods that can be used to focus on areas rather than on individual objects. It defines Depth of Field (DOF) and the factors that affect it. It distinguishes between different lens types and presents the effects of each lens type. It also provides suggestions on how to minimize the Diffraction effect that can adversely affect the most critical images. Camera resolution is the ability of the camera system, which includes the lens optics, camera sensor (film or a digital sensor), and image-processing software, to distinguish, or “resolve” groups of alternating line pairs as the lines become increasingly thinner and they become increasingly closer together. Acutance refers to the cameras ability to render a sharp edge of the subject as a sharp edge in the photograph. There are three camera variables that directly affect the DOF range that includes F/stop choice, lens choice, and camera-to-subject distance.

Chapter 4 – Basic Exposure (Nonflash) Concepts

This chapter explains the photographic variables related to exposure. It provides information required to control motion and eliminate blur in photographs. Determining the proper exposure for an image is an essential element of crime scene photography. Each exposure variable affects the others. One variable can be changed if another is also changed to maintain exposure equilibrium. The same overall exposure can be achieved with different exposure settings. This allows the photographer to capture a properly exposed image with different effects: different motion-stopping capability and different ranges of depth of field. The exposure meter is the “tool” used to determine a proper exposure. It indicates whether a “proper” exposure has been established or whether the scene is currently overexposed or underexposed. Shutter speeds are not only exposure controls but also motion controls. The proper choice of shutter speeds not only eliminates the risk of blurred photographs resulting from the movement of the photographer at the instant the shutter is depressed but can also eliminate the blur that can be caused by the movement of subjects and objects within well-composed photographs.

Chapter 6 – Electronic Flash

This chapter explains the need to use the cameras designated sync shutter speed. It explains various techniques by which a crime scene photographer can control the flash output. It also explains bracketing with flash. It concludes with the benefits of bounce flash and the ways to use this technique. Many flash units allow the crime scene photographer to choose from the manual, automatic, or dedicated flash exposure modes. The more controls that any photographer has at his or her disposal, the more precision that can be expected in the final product: a well-exposed photograph. Some techniques may work under certain circumstances, and others may work better in other conditions. The common exposure errors that may be encountered were pointed out. When wide extremes of light are in the scene, ranging from extremely bright areas to very dark areas, the sensor, by itself, will not be able to capture details in both of these extremes. Details will be lost either in the highlight areas or in the shadow areas. Some areas will be either overexposed or badly underexposed. Rather than lose potentially important information in either area, photographer can use fill-in flash to ensure that details in both exposure extremes are captured. Certain types of evidence are best lit with the light coming from the side. Reflectors can also be used to soften the hard shadows cast by oblique flash and illuminate evidence hidden in the shadow area.

Chapter 2 – Composition and Cardinal Rules

This chapter emphasizes the need to develop a photographer’s eye and consider the elements of composition. It stresses several elements of composition. It suggests that photographers must first consider their own viewpoint of the subject. The same object or area may be best viewed from one direction rather than from another direction. What considerations may affect this choice? One viewpoint may include too many distracting elements, which are easily eliminated from a different viewpoint. One viewpoint may include the photographer’s shadow, which should always be avoided if possible. If it is impossible to exclude a partial shadow from being seen from one viewpoint, then totally covering a small area in shadow should be considered. Once the “primary subject” is determined, additional elements in the foreground and background and to the left and to the right of the “primary subject” should be eliminated from the field of view. This can sometimes be accomplished best by framing the subject with the camera held either horizontally or vertically, depending on the shape of the subject. Composition suggests that the photographer makes choices to optimally frame the subject matter. Composition should be as carefully considered as either exposure issues or focusing techniques.

Chapter 9 – Special Photography Situations

This chapter covers a wide variety of specialized photography which expands upon the traditional photographic documentation of crime scenes and the evidence within them. Written by experts in their subject matter, these sections include: Aerial photography: Specific issues are exposure variables, controlling the motion/vibration of the aircraft so that blur is avoided, and additional safety procedures. Autopsy photography: This section provides the knowledge of autopsy photography standards, common techniques, and tips for special procedures. Bloodstain pattern photography: This is best done when the photographer has had some basic bloodstain pattern analysis training. This section provides examples of such images that need to be captured. Photography from Drones: This section points out the capabilities of drones and highlights the new issues surrounding the images produced by drones. Firearms trajectory photography: Evidence recorded and collected at the scene can support conclusions regarding the types and numbers of firearms involved, the kinds and classifications of ammunition used, and the directions and angles of bullet travel. Surveillance photography: Techniques covered include those required to capture recognizable images of a suspect from a distance in both daytime and nighttime situations. Underwater photography: Issues include additional safety concerns, understanding how water affects both exposure and colors, and managing the “scatter” and “backscatter” caused by particulates suspended in the water. Vehicular crash photography: Many times done by specialized units, recommendations for successful crash scene photography are completely comprehensively covered here.

Chapter 7 – Ultraviolet, Infrared, and Fluorescence

The light that is the foundation of photography is related to the electromagnetic spectrum (EMS). This spectrum depicts light as a wave of radiation, which has a peak height (amplitude), a distance between peaks (wavelength), and a number of complete waves passing a point each second (frequency). When light strikes various surfaces, it can interact with those surfaces differently, and crime scene photographers can use these differences to visualize otherwise “invisible” evidence. Ultraviolet (UV) light can be used to search for faint bloodstains, tracks, or trails. UV light can also cause nonblood body fluids, some fibers, and some fingerprints to fluoresce. The evidence can then be photographed while fluorescing and collected. Infrared (IR) light can also react differently to different substances and substrates, making it possible to visualize various types of evidence not noticed in the visible light range. Inks with different chemical makeup can frequently be distinguished, and gunshot residues on dark fabrics can more easily be seen. Printing or writing on charred documents can sometimes be visualized by the use of IR lighting techniques. Some inks can be made to fluoresce in the IR range when stimulated with blue–green light. Many types of evidence can be made to fluoresce in the visible light range of the EMS, enabling the evidence to be seen, photographed, and then collected.