Monday, March 23, 2009
Blow Flies & Beetles
Information about the development and appearance of some common forensically important insects.
Go directly to the Blow flies or Beetles.
Insects have existed on earth for about 250 million years; comparatively humans have existed for about 300,000 years. Such an enormous amount of time has allowed insects to attain a wide diversity in both form and development. There are currently about 700,000 described species and it is estimated that there may be more than 10 million species of insects yet to be described. Some insects have evolved a gradual or "paurometabolous" development in which there is an egg that hatches into an immature or "nymph", which resembles the adult form, but is smaller and lacks wings. In the forensically important insects, this is best represented by the cockroaches. However, most forensically important insects undergo a complete or "holometabolous" development. There is an egg stage (except for a few insects such as the flesh flies that deposit living larvae) which hatches into a larval form and undergoes a stepwise or incremental growth. This pattern is caused by the successive molts (shedding of the outer skin that has become too small) that the larva must undergo before it finally enters the inactive pupal stage. The pupa is simply the hardened outer skin of the last larval stage and the adult will develop inside of this protective skin.
Blow flies
In the insects that undergo complete development, the larval stages appear quite different from the adult form. The larvae of flies (order Diptera) that are commonly recovered from decomposing human remains lack functional legs, and the body of many species appears cream colored, soft-bodied, and quite "maggot-like". For a picture of some of the maggots commonly found on human cadavers click here. Once the larva or "maggot" is through feeding it will migrate away from the corpse in order to find a suitable site to form the pupal stage. The pupae of blow flies are often overlooked, as they closely resemble rat droppings or the egg case of cockroaches. The pupal stage is an extremely important stage to the forensic entomologist and a thorough search should be made for the presence of pupae at any death scene. If the adult insect has not emerged, the pupa will appear featureless and rounded on both ends. For a picture of a blow fly pupa click here. If the adult insect has emerged, one end will appear as if it has been cut off, and the hollow interior will be revealed. For a picture of an adult emerging from the puparium click here. Most adult blow flies appear a metallic green or blue and are easily recognizable. For a picture of two common adult blow flies click here.
Beetles
The beetles (order Coleoptera) are one of the largest groups of animals and they also undergo complete development. Because of their development the larvae appear very different from the adult form. Although the larvae or "maggots" of a large number of blow fly species may look almost identical; the larvae of beetles may look very different from one species to the next. Beetle larvae recovered from corpses can be easily differentiated from maggots as they have 3 pairs of legs and the maggots found on decomposing remains will not have any legs. Once a larva as been identified as that of a beetle, further field identification can be accomplished because of the wide diversity of larval forms. The bodies of beetle larvae may range from almost white, robust, and hairless to dark brown, slender, and quite hairy. Others may appear almost black and have armored plates on their back. For a picture of some of the most common beetle larvae click here. Although the number and appearance of adult beetles that can be found on human remains is much too diverse to show even a representative sample, two of the most common carrion beetles can be viewed by clicking here.
Go directly to the Blow flies or Beetles.
Insects have existed on earth for about 250 million years; comparatively humans have existed for about 300,000 years. Such an enormous amount of time has allowed insects to attain a wide diversity in both form and development. There are currently about 700,000 described species and it is estimated that there may be more than 10 million species of insects yet to be described. Some insects have evolved a gradual or "paurometabolous" development in which there is an egg that hatches into an immature or "nymph", which resembles the adult form, but is smaller and lacks wings. In the forensically important insects, this is best represented by the cockroaches. However, most forensically important insects undergo a complete or "holometabolous" development. There is an egg stage (except for a few insects such as the flesh flies that deposit living larvae) which hatches into a larval form and undergoes a stepwise or incremental growth. This pattern is caused by the successive molts (shedding of the outer skin that has become too small) that the larva must undergo before it finally enters the inactive pupal stage. The pupa is simply the hardened outer skin of the last larval stage and the adult will develop inside of this protective skin.
Blow flies
In the insects that undergo complete development, the larval stages appear quite different from the adult form. The larvae of flies (order Diptera) that are commonly recovered from decomposing human remains lack functional legs, and the body of many species appears cream colored, soft-bodied, and quite "maggot-like". For a picture of some of the maggots commonly found on human cadavers click here. Once the larva or "maggot" is through feeding it will migrate away from the corpse in order to find a suitable site to form the pupal stage. The pupae of blow flies are often overlooked, as they closely resemble rat droppings or the egg case of cockroaches. The pupal stage is an extremely important stage to the forensic entomologist and a thorough search should be made for the presence of pupae at any death scene. If the adult insect has not emerged, the pupa will appear featureless and rounded on both ends. For a picture of a blow fly pupa click here. If the adult insect has emerged, one end will appear as if it has been cut off, and the hollow interior will be revealed. For a picture of an adult emerging from the puparium click here. Most adult blow flies appear a metallic green or blue and are easily recognizable. For a picture of two common adult blow flies click here.
Beetles
The beetles (order Coleoptera) are one of the largest groups of animals and they also undergo complete development. Because of their development the larvae appear very different from the adult form. Although the larvae or "maggots" of a large number of blow fly species may look almost identical; the larvae of beetles may look very different from one species to the next. Beetle larvae recovered from corpses can be easily differentiated from maggots as they have 3 pairs of legs and the maggots found on decomposing remains will not have any legs. Once a larva as been identified as that of a beetle, further field identification can be accomplished because of the wide diversity of larval forms. The bodies of beetle larvae may range from almost white, robust, and hairless to dark brown, slender, and quite hairy. Others may appear almost black and have armored plates on their back. For a picture of some of the most common beetle larvae click here. Although the number and appearance of adult beetles that can be found on human remains is much too diverse to show even a representative sample, two of the most common carrion beetles can be viewed by clicking here.
Forensics and Entomology
Introduction
This site was created in order to assist in the education of crime scene technicians, homicide investigators, coroners, medical examiners, and others involved in the death investigation process. A basic knowledge of the general appearance of insect of forensic importance, and a basic understanding of the proper methods for their collection, will allow investigators to make accurate and representative collections from the death scene. Enhanced knowledge on the behalf of law enforcement officials will provide for better communication between police, medical examiners, coroners, and forensic entomologists. Hopefully, improved communication will promote more frequent use of entomological resources, and more accurate collection of entomological evidence. This will allow forensic entomologists to be more precise in their statements and determinations, particularly in the area of postmortem interval estimations. Those involved in crime scene analysis and the death investigation process are encouraged to use this site as a reference resource to enhance their investigation efforts. It is impossible to determine when insect evidence my prove useful in a death investigation. Therefore, all law enforcement agencies should assemble a "Entomological Evidence Collection Kit" so that they are prepared in the event entomological evidence is encountered during any crime scene investigation.
If you would like to contact a Board Certified Forensic Entomologist (Click Here).
This site was created in order to assist in the education of crime scene technicians, homicide investigators, coroners, medical examiners, and others involved in the death investigation process. A basic knowledge of the general appearance of insect of forensic importance, and a basic understanding of the proper methods for their collection, will allow investigators to make accurate and representative collections from the death scene. Enhanced knowledge on the behalf of law enforcement officials will provide for better communication between police, medical examiners, coroners, and forensic entomologists. Hopefully, improved communication will promote more frequent use of entomological resources, and more accurate collection of entomological evidence. This will allow forensic entomologists to be more precise in their statements and determinations, particularly in the area of postmortem interval estimations. Those involved in crime scene analysis and the death investigation process are encouraged to use this site as a reference resource to enhance their investigation efforts. It is impossible to determine when insect evidence my prove useful in a death investigation. Therefore, all law enforcement agencies should assemble a "Entomological Evidence Collection Kit" so that they are prepared in the event entomological evidence is encountered during any crime scene investigation.
If you would like to contact a Board Certified Forensic Entomologist (Click Here).
AAA Statement on Race
ABOUT THE PROJECT
AAA's Statement on Race
AMERICAN ANTHROPOLOGICAL ASSOCIATION STATEMENT ON "RACE" (May 17, 1998)
The following statement was adopted by the Executive Board of the American Anthropological Association, acting on a draft prepared by a committee of representative American anthropologists. It does not reflect a consensus of all members of the AAA, as individuals vary in their approaches to the study of "race." We believe that it represents generally the contemporary thinking and scholarly positions of a majority of anthropologists.
In the United States both scholars and the general public have been conditioned to viewing human races as natural and separate divisions within the human species based on visible physical differences. With the vast expansion of scientific knowledge in this century, however, it has become clear that human populations are not unambiguous, clearly demarcated, biologically distinct groups. Evidence from the analysis of genetics (e.g., DNA) indicates that most physical variation, about 94%, lies within so-called racial groups. Conventional geographic "racial" groupings differ from one another only in about 6% of their genes. This means that there is greater variation within "racial" groups than between them. In neighboring populations there is much overlapping of genes and their phenotypic (physical) expressions. Throughout history whenever different groups have come into contact, they have interbred. The continued sharing of genetic materials has maintained all of humankind as a single species.
Physical variations in any given trait tend to occur gradually rather than abruptly over geographic areas. And because physical traits are inherited independently of one another, knowing the range of one trait does not predict the presence of others. For example, skin color varies largely from light in the temperate areas in the north to dark in the tropical areas in the south; its intensity is not related to nose shape or hair texture. Dark skin may be associated with frizzy or kinky hair or curly or wavy or straight hair, all of which are found among different indigenous peoples in tropical regions. These facts render any attempt to establish lines of division among biological populations both arbitrary and subjective.
Historical research has shown that the idea of "race" has always carried more meanings than mere physical differences; indeed, physical variations in the human species have no meaning except the social ones that humans put on them. Today scholars in many fields argue that "race" as it is understood in the United States of America was a social mechanism invented during the 18th century to refer to those populations brought together in colonial America: the English and other European settlers, the conquered Indian peoples, and those peoples of Africa brought in to provide slave labor.
From its inception, this modern concept of "race" was modeled after an ancient theorem of the Great Chain of Being, which posited natural categories on a hierarchy established by God or nature. Thus "race" was a mode of classification linked specifically to peoples in the colonial situation. It subsumed a growing ideology of inequality devised to rationalize European attitudes and treatment of the conquered and enslaved peoples. Proponents of slavery in particular during the 19th century used "race" to justify the retention of slavery. The ideology magnified the differences among Europeans, Africans, and Indians, established a rigid hierarchy of socially exclusive categories underscored and bolstered unequal rank and status differences, and provided the rationalization that the inequality was natural or God-given. The different physical traits of African-Americans and Indians became markers or symbols of their status differences.
As they were constructing US society, leaders among European-Americans fabricated the cultural/behavioral characteristics associated with each "race," linking superior traits with Europeans and negative and inferior ones to blacks and Indians. Numerous arbitrary and fictitious beliefs about the different peoples were institutionalized and deeply embedded in American thought.
Early in the 19th century the growing fields of science began to reflect the public consciousness about human differences. Differences among the "racial" categories were projected to their greatest extreme when the argument was posed that Africans, Indians, and Europeans were separate species, with Africans the least human and closer taxonomically to apes.
Ultimately "race" as an ideology about human differences was subsequently spread to other areas of the world. It became a strategy for dividing, ranking, and controlling colonized people used by colonial powers everywhere. But it was not limited to the colonial situation. In the latter part of the 19th century it was employed by Europeans to rank one another and to justify social, economic, and political inequalities among their peoples. During World War II, the Nazis under Adolf Hitler enjoined the expanded ideology of "race" and "racial" differences and took them to a logical end: the extermination of 11 million people of "inferior races" (e.g., Jews, Gypsies, Africans, homosexuals, and so forth) and other unspeakable brutalities of the Holocaust.
"Race" thus evolved as a worldview, a body of prejudgments that distorts our ideas about human differences and group behavior. Racial beliefs constitute myths about the diversity in the human species and about the abilities and behavior of people homogenized into "racial" categories. The myths fused behavior and physical features together in the public mind, impeding our comprehension of both biological variations and cultural behavior, implying that both are genetically determined. Racial myths bear no relationship to the reality of human capabilities or behavior. Scientists today find that reliance on such folk beliefs about human differences in research has led to countless errors.
At the end of the 20th century, we now understand that human cultural behavior is learned, conditioned into infants beginning at birth, and always subject to modification. No human is born with a built-in culture or language. Our temperaments, dispositions, and personalities, regardless of genetic propensities, are developed within sets of meanings and values that we call "culture." Studies of infant and early childhood learning and behavior attest to the reality of our cultures in forming who we are.
It is a basic tenet of anthropological knowledge that all normal human beings have the capacity to learn any cultural behavior. The American experience with immigrants from hundreds of different language and cultural backgrounds who have acquired some version of American culture traits and behavior is the clearest evidence of this fact. Moreover, people of all physical variations have learned different cultural behaviors and continue to do so as modern transportation moves millions of immigrants around the world.
How people have been accepted and treated within the context of a given society or culture has a direct impact on how they perform in that society. The "racial" worldview was invented to assign some groups to perpetual low status, while others were permitted access to privilege, power, and wealth. The tragedy in the United States has been that the policies and practices stemming from this worldview succeeded all too well in constructing unequal populations among Europeans, Native Americans, and peoples of African descent. Given what we know about the capacity of normal humans to achieve and function within any culture, we conclude that present-day inequalities between so-called "racial" groups are not consequences of their biological inheritance but products of historical and contemporary social, economic, educational, and political circumstances.
[Note: For further information on human biological variations, see the statement prepared and issued by the American Association of Physical Anthropologists, 1996 (AJPA 101:569-570).]
AAA POSITION PAPER ON "RACE": COMMENTS?
As a result of public confusion about the meaning of "race," claims as to major biological differences among "races" continue to be advanced. Stemming from past AAA actions designed to address public misconceptions on race and intelligence, the need was apparent for a clear AAA statement on the biology and politics of race that would be educational and informational. Rather than wait for each spurious claim to be raised, the AAA Executive Board determined that the Association should prepare a statement for approval by the Association and elicit member input.
Commissioned by the Executive Board of the American Anthropological Association, a position paper on race was authored by Audrey Smedley (Race in North America: Origin and Evolution of a Worldview, 1993) and thrice reviewed by a working group of prominent anthropologists: George Armelagos, Michael Blakey, C. Loring Brace, Alan Goodman, Faye Harrison, Jonathan Marks, Yolanda Moses, and Carol Mukhopadhyay. A draft of the current paper was published in the September 1997 Anthropology Newsletter and posted ont the AAA website http://www.aaanet.org for a number of months, and member comments were requested. While Smedley assumed authorship of the final draft, she received comments not only from the working group but also from the AAA membership and other interested readers. The paper above was adopted by the AAA Executive Board on May 17, 1998, as an official statement of AAA's position on "race."
As the paper is considered a living statement, AAA members', other anthropologists', and public comments are invited. Your comments may be sent via mail or e-mail to Peggy Overbey, Director of Government Relations, American Anthropological Association, 4350 N. Fairfax Dr., Suite 640, Arlington, VA 22201.
AAA's Statement on Race
AMERICAN ANTHROPOLOGICAL ASSOCIATION STATEMENT ON "RACE" (May 17, 1998)
The following statement was adopted by the Executive Board of the American Anthropological Association, acting on a draft prepared by a committee of representative American anthropologists. It does not reflect a consensus of all members of the AAA, as individuals vary in their approaches to the study of "race." We believe that it represents generally the contemporary thinking and scholarly positions of a majority of anthropologists.
In the United States both scholars and the general public have been conditioned to viewing human races as natural and separate divisions within the human species based on visible physical differences. With the vast expansion of scientific knowledge in this century, however, it has become clear that human populations are not unambiguous, clearly demarcated, biologically distinct groups. Evidence from the analysis of genetics (e.g., DNA) indicates that most physical variation, about 94%, lies within so-called racial groups. Conventional geographic "racial" groupings differ from one another only in about 6% of their genes. This means that there is greater variation within "racial" groups than between them. In neighboring populations there is much overlapping of genes and their phenotypic (physical) expressions. Throughout history whenever different groups have come into contact, they have interbred. The continued sharing of genetic materials has maintained all of humankind as a single species.
Physical variations in any given trait tend to occur gradually rather than abruptly over geographic areas. And because physical traits are inherited independently of one another, knowing the range of one trait does not predict the presence of others. For example, skin color varies largely from light in the temperate areas in the north to dark in the tropical areas in the south; its intensity is not related to nose shape or hair texture. Dark skin may be associated with frizzy or kinky hair or curly or wavy or straight hair, all of which are found among different indigenous peoples in tropical regions. These facts render any attempt to establish lines of division among biological populations both arbitrary and subjective.
Historical research has shown that the idea of "race" has always carried more meanings than mere physical differences; indeed, physical variations in the human species have no meaning except the social ones that humans put on them. Today scholars in many fields argue that "race" as it is understood in the United States of America was a social mechanism invented during the 18th century to refer to those populations brought together in colonial America: the English and other European settlers, the conquered Indian peoples, and those peoples of Africa brought in to provide slave labor.
From its inception, this modern concept of "race" was modeled after an ancient theorem of the Great Chain of Being, which posited natural categories on a hierarchy established by God or nature. Thus "race" was a mode of classification linked specifically to peoples in the colonial situation. It subsumed a growing ideology of inequality devised to rationalize European attitudes and treatment of the conquered and enslaved peoples. Proponents of slavery in particular during the 19th century used "race" to justify the retention of slavery. The ideology magnified the differences among Europeans, Africans, and Indians, established a rigid hierarchy of socially exclusive categories underscored and bolstered unequal rank and status differences, and provided the rationalization that the inequality was natural or God-given. The different physical traits of African-Americans and Indians became markers or symbols of their status differences.
As they were constructing US society, leaders among European-Americans fabricated the cultural/behavioral characteristics associated with each "race," linking superior traits with Europeans and negative and inferior ones to blacks and Indians. Numerous arbitrary and fictitious beliefs about the different peoples were institutionalized and deeply embedded in American thought.
Early in the 19th century the growing fields of science began to reflect the public consciousness about human differences. Differences among the "racial" categories were projected to their greatest extreme when the argument was posed that Africans, Indians, and Europeans were separate species, with Africans the least human and closer taxonomically to apes.
Ultimately "race" as an ideology about human differences was subsequently spread to other areas of the world. It became a strategy for dividing, ranking, and controlling colonized people used by colonial powers everywhere. But it was not limited to the colonial situation. In the latter part of the 19th century it was employed by Europeans to rank one another and to justify social, economic, and political inequalities among their peoples. During World War II, the Nazis under Adolf Hitler enjoined the expanded ideology of "race" and "racial" differences and took them to a logical end: the extermination of 11 million people of "inferior races" (e.g., Jews, Gypsies, Africans, homosexuals, and so forth) and other unspeakable brutalities of the Holocaust.
"Race" thus evolved as a worldview, a body of prejudgments that distorts our ideas about human differences and group behavior. Racial beliefs constitute myths about the diversity in the human species and about the abilities and behavior of people homogenized into "racial" categories. The myths fused behavior and physical features together in the public mind, impeding our comprehension of both biological variations and cultural behavior, implying that both are genetically determined. Racial myths bear no relationship to the reality of human capabilities or behavior. Scientists today find that reliance on such folk beliefs about human differences in research has led to countless errors.
At the end of the 20th century, we now understand that human cultural behavior is learned, conditioned into infants beginning at birth, and always subject to modification. No human is born with a built-in culture or language. Our temperaments, dispositions, and personalities, regardless of genetic propensities, are developed within sets of meanings and values that we call "culture." Studies of infant and early childhood learning and behavior attest to the reality of our cultures in forming who we are.
It is a basic tenet of anthropological knowledge that all normal human beings have the capacity to learn any cultural behavior. The American experience with immigrants from hundreds of different language and cultural backgrounds who have acquired some version of American culture traits and behavior is the clearest evidence of this fact. Moreover, people of all physical variations have learned different cultural behaviors and continue to do so as modern transportation moves millions of immigrants around the world.
How people have been accepted and treated within the context of a given society or culture has a direct impact on how they perform in that society. The "racial" worldview was invented to assign some groups to perpetual low status, while others were permitted access to privilege, power, and wealth. The tragedy in the United States has been that the policies and practices stemming from this worldview succeeded all too well in constructing unequal populations among Europeans, Native Americans, and peoples of African descent. Given what we know about the capacity of normal humans to achieve and function within any culture, we conclude that present-day inequalities between so-called "racial" groups are not consequences of their biological inheritance but products of historical and contemporary social, economic, educational, and political circumstances.
[Note: For further information on human biological variations, see the statement prepared and issued by the American Association of Physical Anthropologists, 1996 (AJPA 101:569-570).]
AAA POSITION PAPER ON "RACE": COMMENTS?
As a result of public confusion about the meaning of "race," claims as to major biological differences among "races" continue to be advanced. Stemming from past AAA actions designed to address public misconceptions on race and intelligence, the need was apparent for a clear AAA statement on the biology and politics of race that would be educational and informational. Rather than wait for each spurious claim to be raised, the AAA Executive Board determined that the Association should prepare a statement for approval by the Association and elicit member input.
Commissioned by the Executive Board of the American Anthropological Association, a position paper on race was authored by Audrey Smedley (Race in North America: Origin and Evolution of a Worldview, 1993) and thrice reviewed by a working group of prominent anthropologists: George Armelagos, Michael Blakey, C. Loring Brace, Alan Goodman, Faye Harrison, Jonathan Marks, Yolanda Moses, and Carol Mukhopadhyay. A draft of the current paper was published in the September 1997 Anthropology Newsletter and posted ont the AAA website http://www.aaanet.org for a number of months, and member comments were requested. While Smedley assumed authorship of the final draft, she received comments not only from the working group but also from the AAA membership and other interested readers. The paper above was adopted by the AAA Executive Board on May 17, 1998, as an official statement of AAA's position on "race."
As the paper is considered a living statement, AAA members', other anthropologists', and public comments are invited. Your comments may be sent via mail or e-mail to Peggy Overbey, Director of Government Relations, American Anthropological Association, 4350 N. Fairfax Dr., Suite 640, Arlington, VA 22201.
Latent Print Photography
Minutiæ Issue #46
Latent Print Photography - Pat A. Wertheim
This article is the fifth in a comprehensive series of articles on latent print development techniques written by Pat A. Wertheim, Director of Training for Forensic Identification Training Seminars, Ltd. Watch for future articles in each issue of Minutiæ and save these issues in a binder to compile a manual of fingerprint development techniques.
In the early days of latent print science, clear adhesive tape had not yet been invented and the only way to record a latent print was by photography. Of course, the 35mm SLR camera had not been invented, either, and the camera of the day was the 4" x 5" sheet film camera. Because of the training required to use those old cameras, it was far easier to hire a trained photographer and teach him latent prints than to hire someone who knew neither fingerprints nor photography. Even though black and white was the only film available, colored powders were selected to provide maximum contrast with the background on which the latent was developed, and colored filters were used to enhance that contrast. Excellent images resulted. Latent print photography by those standards is all but a lost art.
Large format, 4" x 5" cameras are still used in most major fingerprint laboratories, the Polaroid MP-4 being the most common camera of this type in use today. Although the MP-4, or any other 4" x 5" camera, is capable of refined fingerprint photography techniques that are difficult with a smaller format 35mm, some of these techniques may actually be used with a 35mm with a little effort and practice. One point to keep in mind, however, is that frequently, fingerprint photography requires the use of light in ways not used, or even avoided, in other types of photography. The following three methods may be used with either the large format cameras or small format cameras. With a 4" x 5" camera, pictures would be taken at 1-to-1 scale. With a 35mm, they should be taken with the closest focal range possible and the smallest ƒ/stop to maximize depth of field, using long exposure times and focusing by moving the camera closer or farther from the object as needed for correct focus. As much as possible, a 90° angle should be maintained between the camera direction and the surface being photographed. Neither type camera should be hand held for fingerprint photography, but must be mounted firmly on a copy stand or sturdy tripod.
The most common method used is photography by "direct light." This method of fingerprint photography is used for fingerprints of good contrast plainly visible to the naked eye. The camera is aimed straight at the fingerprint with one or more light sources shining from about a 45° angle. In reality, this is simply normal photography, the same way you would photograph people or scenes.
The second most common type of fingerprint photography is with "direct reflected light." This method is used for prints that you can see only by manipulating the surface to catch the glare of some light source. The camera is aimed at the surface in a manner to catch the fingerprint image highlighted in the glare. This method is especially good on perfectly flat, shiny surfaces. For example, it works very well on plastic garbage bags after glue fuming when the fingerprints have not come up in well-developed white prints. Stretch the area of plastic with a print tightly over a beaker or end of a can to hold it flat, securing the plastic firmly with a rubber band to keep it stretched. Focus down on the print, using an overhead ceiling light to provide the necessary glare to highlight the print.
The third method is with the use of what might be described as "oblique transmitted light." This method is particularly good for photographing glue-fumed prints on clear plastic film such as cling wrap or plastic baggies. Stretch the clear plastic material over a glass beaker or wide mouth jar with the print centered over the opening, again using a rubber band to hold it in place. Cut out some various sized circles of black paper, from 1" diameter to 4" diameter. If a light table is available, place an appropriately sized black circle on the table under the beaker, so that the light is blocked from the print itself in the view of the camera. This will produce a crisp white fingerprint on a black background. If no light table is available, some experimentation and imagination may be required to figure out how to get the light source to shine through the plastic material with the black background under the print, but the results will be worth the effort.
In the next issue of Minutiæ, Pat will write about using iodine and silver nitrate to develop latent prints on porous surfaces.
Latent Print Photography - Pat A. Wertheim
This article is the fifth in a comprehensive series of articles on latent print development techniques written by Pat A. Wertheim, Director of Training for Forensic Identification Training Seminars, Ltd. Watch for future articles in each issue of Minutiæ and save these issues in a binder to compile a manual of fingerprint development techniques.
In the early days of latent print science, clear adhesive tape had not yet been invented and the only way to record a latent print was by photography. Of course, the 35mm SLR camera had not been invented, either, and the camera of the day was the 4" x 5" sheet film camera. Because of the training required to use those old cameras, it was far easier to hire a trained photographer and teach him latent prints than to hire someone who knew neither fingerprints nor photography. Even though black and white was the only film available, colored powders were selected to provide maximum contrast with the background on which the latent was developed, and colored filters were used to enhance that contrast. Excellent images resulted. Latent print photography by those standards is all but a lost art.
Large format, 4" x 5" cameras are still used in most major fingerprint laboratories, the Polaroid MP-4 being the most common camera of this type in use today. Although the MP-4, or any other 4" x 5" camera, is capable of refined fingerprint photography techniques that are difficult with a smaller format 35mm, some of these techniques may actually be used with a 35mm with a little effort and practice. One point to keep in mind, however, is that frequently, fingerprint photography requires the use of light in ways not used, or even avoided, in other types of photography. The following three methods may be used with either the large format cameras or small format cameras. With a 4" x 5" camera, pictures would be taken at 1-to-1 scale. With a 35mm, they should be taken with the closest focal range possible and the smallest ƒ/stop to maximize depth of field, using long exposure times and focusing by moving the camera closer or farther from the object as needed for correct focus. As much as possible, a 90° angle should be maintained between the camera direction and the surface being photographed. Neither type camera should be hand held for fingerprint photography, but must be mounted firmly on a copy stand or sturdy tripod.
The most common method used is photography by "direct light." This method of fingerprint photography is used for fingerprints of good contrast plainly visible to the naked eye. The camera is aimed straight at the fingerprint with one or more light sources shining from about a 45° angle. In reality, this is simply normal photography, the same way you would photograph people or scenes.
The second most common type of fingerprint photography is with "direct reflected light." This method is used for prints that you can see only by manipulating the surface to catch the glare of some light source. The camera is aimed at the surface in a manner to catch the fingerprint image highlighted in the glare. This method is especially good on perfectly flat, shiny surfaces. For example, it works very well on plastic garbage bags after glue fuming when the fingerprints have not come up in well-developed white prints. Stretch the area of plastic with a print tightly over a beaker or end of a can to hold it flat, securing the plastic firmly with a rubber band to keep it stretched. Focus down on the print, using an overhead ceiling light to provide the necessary glare to highlight the print.
The third method is with the use of what might be described as "oblique transmitted light." This method is particularly good for photographing glue-fumed prints on clear plastic film such as cling wrap or plastic baggies. Stretch the clear plastic material over a glass beaker or wide mouth jar with the print centered over the opening, again using a rubber band to hold it in place. Cut out some various sized circles of black paper, from 1" diameter to 4" diameter. If a light table is available, place an appropriately sized black circle on the table under the beaker, so that the light is blocked from the print itself in the view of the camera. This will produce a crisp white fingerprint on a black background. If no light table is available, some experimentation and imagination may be required to figure out how to get the light source to shine through the plastic material with the black background under the print, but the results will be worth the effort.
In the next issue of Minutiæ, Pat will write about using iodine and silver nitrate to develop latent prints on porous surfaces.
Monday, March 2, 2009
Forensic Anthropologists
What is Forensic Anthropology?
Generally speaking forensic anthropology is the examination of human skeletal remains for law enforcement agencies to determine the identity of unidentified bones.
Further definition of the term is necessary to understand the scope and basis of forensic anthropology. Anthropology alone is the study of man. Anthropologists are interested in culture (cultural anthropologists), language (linguistic anthropologists), the physical remains or artifacts left behind by human occupation (archaeologists), and human remains or bones and teeth (physical anthropologists).
Over the past century physical anthropologists (those who study human remains) have developed methods to evaluate bones to figure out things about people who lived in the past. These techniques help them to answer questions about the remains they are studying.
The questions that might be looked into include: Was this individual male or female? How old were they when they died? How tall were they? Were the people studied in good or poor general health?
Forensic anthropology involves the application of these same methods to modern cases of unidentified human remains. Through the established methods, a forensic anthropologist can aid law enforcement in establishing a profile on the unidentified remains. The profile includes sex, age, ethnicity, height, length of time since death, and sometimes the evaluation of trauma seen on bones.
In many cases after identity of an individual is made, the forensic anthropologist is called to testify in court regarding the identity of the remains and/or the trauma or wounds present on the remains.
What do forensic anthropologists do?
Forensic anthropologists are commonly portrayed in the media as forensic scientists and/or crime scene technicians, but this is not accurate. Forensic anthropologists deal strictly with the human remains. While some people trained in forensic anthropology are also trained in evidence collection techniques, most forensic anthropologists only specialize in techniques related to analysis of the remains or bones only.
Generally, forensic anthropologists do not do any of the following:
•Collect trace evidence (hair, fibers)
•Run DNA tests
•Analyze ballistics or weapon evidence
•Analyze blood spatter
•Conduct autopsies
What a forensic anthropologist does do to aid in a case:
•Goes to a crime scene to assist in the collection of human remains
•Cleans up the bones so that they may be looked at
•Analyzes skeletal remains to establish the profile of the individual
•Looks at trauma evident on the bones to establish the pathway of a bullet or the number of stab wounds
•Works with a forensic odontologist (dentist) to match dental records
•Testifies in court about the identity of the individual and/or the injuries that might be evident in the skeleton
What training do forensic anthropologists need?
Current minimum requirements necessary to become a forensic anthropologist include a Bachelor's degree in anthropology or a closely related field, a Master's degree in anthropology, and usually a PhD in physical anthropology.
Additionally, during their education the student must seek out opportunities to gain experience by assisting an established forensic anthropologist with casework.
After the PhD, there is still additional training to complete. Though not a requirement, the American Board of Forensic Anthropology recognizes established forensic anthropologists as diplomates after the required educational requirements are met and the candidate successfully completes written and practical exams.
Where do forensic anthropologists work?
Forensic anthropologists are employed primarily at universities and forensic facilities around the country. Most forensic anthropologists teach and perform research in other areas of anthropology in addition to their casework. Some forensic anthropologists have found jobs in forensic facilities where they work closely with medical examiners or forensic pathologists.
What are examples of cases forensic anthropologists work on?
Here are two case scenarios where the assistance of a forensic anthropologist would be necessary:
Case 1: A hunter is in the woods and comes across what he thinks is a human skull. He marks the area and goes to get police to bring them back to the area. A forensic anthropologist might be called to assist in determining first of all if the remains are in fact human. If the remains are human then the anthropologist can assist law enforcement with the collection of the remains at the scene. Typically the anthropologist would photograph the remains prior to removal and also make a pictorial view or site map of the area so that if need be the scene could be recreated later. During the scene work the anthropologist would work with other crime scene specialists who might be interested in other evidence that cold be found at the scene such as weapons, blood, DNA, etc. Forensic anthropologists can then look at the bones to establish a profile of the remains including the age, sex, ethnicity, height, time since death, and trauma. If the police have a missing person in mind, the forensic anthropologist can then work with the medical examiner and forensic odontologist to determine if the identity is a match.
Case 2: A forensic pathologist is presented with partially decomposed remains of an individual and the identity has already been established. However, there is evidence of multiple traumatic injuries (example: gun shot wounds and/or knife wounds) that occurred close to the time of death and the state of the remains prevents the pathologist from being able to fully understand the extent of the trauma to the remains. The forensic anthropologist aids the pathologist by cleaning the bones and looking closely at them to determine the number and type of traumatic episodes. Through their analyses the forensic anthropologist is able to identify multiple types of traumatic injury, potentially an important factor in the trial.
University of Tennessee Forensic Anthropology Center
Who is Clyde Snow?
Clyde Snow
1928 -
Clyde Snow is perhaps the most famous forensic anthropologists in the world today. He prefers to call his work, "osteobiography" saying, "there is a brief but very useful and informative biography of an individual contained within the skeleton, if you know how to read it" (Current Biography 52).
He was born in Fort Worth, Texas on January 7, 1928 to Wister Clyde Snow and Sarah Isabel Snow. His father was a doctor, so Clyde was frequently shuttled around on house calls with his parents, learning much about medicine, life and death. His first encounter with bones happened when he was twelve on a hunting trip with his father. His dad helped identify some mysterious bones which turned out to be a mule deer along with a man who had been missing for a few years (Current Biography 53).
Snow's scholastic achievements in school started somewhat shaky. During his sophomore year in high school he was expelled for a particular fire cracker incident. He then transferred to the New Mexico Military Institute in Roswell, where his grades dropped until a fellow student showed him how to study. He managed to get his Associates Degree there. Next he attended Southern Methodist University in Dallas and decided that having fun would be his main priority and promptly flunked out. By 1951 though he had earned his Bachelors Degree from Eastern New Mexico University and continued straight into Texas Technical University to get his masters degree in Zoology. The next three years he served as a Lieutenant in the U.S. Air Force Medical Service Corps at the Histopathology Center. In 1958, he enrolled at the University of Arizona, to study Archaeology. He later switched to Anthropology, and received his Ph.D. studying the growth of Savannah baboons (Current Biography 53).
It was 1967 and he had already been working at the Civil Aeromedical Institute (CAMI) for six years where he studied airplane crash fatalities. Snow would examine the remains to determine the cause of death and CAMI would use this information to update and improve airline safety and precautions. Here he began to develop his interest and skills in Forensic Anthropology and eventually became the Head of the department in 1968. His reputation grew from there and in 1972 the American Academy of Forensic Sciences acknowledged forensic work as a specialty within the discipline of anthropology (Huyghe 165).
By 1979 he decided to focus solely on forensics. Here is a compilation of some of his better known skeletal confirmations: John F. Kennedy, the men who fought in General Custer's "last stand" in 1876, Dr. Josef Mengele, the famous Nazi war criminal who fled to Brazil the many victims of serial killer,John Wayne Gacey, Egyptian boy King Tutankhamun and the victims of the Oklahoma bombing (Current Biography 52).
Besides these very public and well known figures he has worked extensively with Americas Watch and other human rights groups. In the 1980's he went to Argentina to exhume mass graves filled with innocent civilians who had been killed by government death squads during the war. He has worked in Argentina, Guatemala, Ethiopia, Philippines, Croatia and others. So far his work has led to the conviction of five officers in Argentina (Huyghe 166). Hundreds of officers were involved of course, but this is a start. More than anything, his work has brought these atrocities to the surface, where the bodies have to be dealt with and questioned by the public and governments.
Currently, Snow is working in former Yugoslavia, near Ovcara. It has become one of the largest forensic excavations ever dealing with war crimes (Stover 40). Snow still teaches at the University of Oklahoma and sometimes lectures to Forensic Science organizations and Law Enforcement personnel. When he's not traveling he lives near Oklahoma City with his wife Jerry Whistler (Current Biography 54). He maintains his Texas roots and personality that may help him cope while wading through so much sadness each day. His advice to co-workers in the field is, "you do the work in the daytime and cry at night" (Green 111).
References:
Current Biography 58.4 (1997):52-54.
Green, Michele. "Dr. Clyde Snow Helps Victims of Argentina's "Dirty War" Bear Witness From the Grave" People Weekly Dec 8, 1986: 111.
Huyghe Patrick. "Clyde Snow The Detective's Detective" Readers Digest 137.823 (1990):165.
Stover Eric. "The Grave at Vukovar" Smithsonian 27.12 (1997):40+.
Written by students in an Introduction to Anthropology course at MSU-Mankato
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