Overview

Sometimes, all that is left from a violent crime are the skeletal remains of the victim. Careful analysis of bones can reveal many important clues about the identity and/or the type of injuries that caused the death of a victim. The scientific examination of the skeletal remains from a crime scene is known as forensic anthropology.

A dead body begins to decompose immediately upon death. The rate at which the human body decomposes depends upon the surrounding environment and the micro-environment of the body. If the remains of a victim have been left outside, insects and micro-organisms accelerate decomposition through infestation. Forensic entomology is a specialized field of forensic science in which the analysis and identification of insects found upon a victim’s body can lead to an approximation of the time of death and the cause of death.

• Lesson 1 of this module discusses forensic anthropology specifically. Then, the lesson shows how human bone can be distinguished from animal bone. Students examine how forensic anthropologists determine both ancestry and sex from skeletal remains.

• Lesson 2 explores how various types of force or various types of weapons can leave specific types of bone fractures.

• Lesson 3 focuses upon how forensic entomologists use information about insect succession to help determine the time and cause of death of a victim whose body is partially decomposed.

• Lesson 4 examines the details of two historical crime cases and one fictional crime case involving forensic anthropology and forensic entomology.

Module Learner Objectives

By the end of Module 6, you should be able to…

• recognize that in the field of forensic anthropology information about the victim of a crime and the nature of the crime itself is determined from unknown skeletal remains

• understand that a forensic anthropologist attempts to determine the following information from unknown skeletal remains: whether they are human or non-human, number of individuals found, time of death, sex of individual(s), ancestry of individual(s), stature of individual(s), and cause of death
• describe some of the basic skeletal differences between human and animal bones (such as ribs and upper and lower limbs)

• state some of the basic skeletal differences between humans of various ancestries or races (such as Negroid, Caucasoid, and Mongoloid)

• identify some of the basic skeletal differences between female and male remains

• perform a research study that compares the size and length of various bones in males and females

• describe how different types of force (such as compression, bending, torsion, tension, shearing) can fracture human bones in specific ways

• explain how various types of trauma (such as blunt force, projectile, sharp force, strangulation) cause specific types of damage to human bone

• describe how various type(s) of weapons can cause damage to human bone

• recognize that the field of forensic entomology helps investigators to determine on the basis of insect infestation the approximate length of time a body has been left in an area

• understand that each environment has a unique set of native insect species and that each of these insects has a unique life cycle and exhibits unique behaviors

• analyze a historical crime case(s) or fictional crime case(s) that involves forensic anthropology and/or forensic entomology

Defining Forensic Anthropology

Anthropology is the study of the biological and cultural aspects of humankind in any place at any time. Two sub-fields of anthropology are

• cultural anthropology – the observation over time of norms, customs, political, economic, and religious systems in a culture
• physical or biological anthropology – the identification and interpretation of human evolution and variation in humans

Forensic anthropology is a specialized field of forensic science in which the goal is to analyze and interpret the human remains of unexplained deaths. Forensic anthropologists conduct their work by analyzing human skeletons or decomposing remains to extract as much information about the person and the circumstances surrounding his or her death. Forensic anthropologists provide this valuable information to a medical examiner, pathologist, or law enforcement officer. A forensic anthropologist analyzes remains according to the following list of questions:

1. Are the remains skeletal?
2. Are the skeletal remains human or animal?
3. Are the skeletal remains modern or historical?
4. How many individuals are present?
5. Is there evidence of time since the death?
6. What is the age, sex, stature, and ancestry of each individual?
7. What are the individualizing features of the remains?
8. Is there evidence that can aid in establishing the cause and manner of death?

The forensic anthropologist creates an osteobiography (bone story) about the deceased remains they examine. This osteobiography includes a description of age, sex, stature, ancestry, and individualizing features such as previous illnesses, genetic abnormalities, and trauma. Determining the age, sex, stature, and ancestry helps to determine if the individual is a missing person. Identification of individualizing features may help to identify a person positively. Forensic anthropologists also look for signs of recent trauma that may have been the cause of death.

If partial skeletal remains are found, especially when no skull is apparent, animal bones may be mistaken for human bones. Distinguishing bones as human or animal may be difficult sometimes.

1. Ribs: The inexperienced observer might confuse sheep ribbones as human ribs because they are slender and similar in size. However, human rib bones tend to be C-shaped, while most animal ribs tend to be more linear/straight (see photograph below). Humans normally have 12 pairs of ribs. However, some may have one more or one less. Most animals have more than 12 pairs of ribs. Sheep have 13 pairs. (See the photograph below.)
   
   

   Animal Rib Bones and Human Rib Bones

   

   The Ribs of a sheep (left) as compared to human ribs (right).

   - Image Source: Courtesy Julie R. Angel (University of New Mexico, Museum of Southwestern Biology), published in Steven N. Beyers. Introduction to Forensic Anthropology: A Textbook (p. 66). Allyn & Bacon (2002).

2. Upper arm bones: Human upper arm bones (humerus) are used for lifting and, thus, tend to be smaller and more slender than animal limb bones. This is because humans are bipedal. Bipedal animals move using two legs; thus, the weight of the body is not carried on the bones within the arms. Most mammals are quadrupeds, which means they bear their weight on four limbs when they move.

   In addition, the upper arm bones of a human have a smaller tubercle on the upper part of the bone. This is because a human shoulder joint is less stable because it lies in a relatively shallow shoulder blade. In other animals, the strong ligamentation around the upper part of the limb bones due to larger muscle attachment sites creates a larger tubercle with projections. (See the photograph below.)

   Examples of Upper Arm or Limb Bones

   Deer Sheep Cow Elk Human

   

   - Image Source: Courtesy Julie R. Angel (University of New Mexico, Museum of Southwestern Biology), published in Steven N. Beyers. Introduction to Forensic Anthropology; A Textbook (p. 68). Allyn & Bacon (2002).

A forensic anthropologist may be able to help determine the ancestry of a victim through an examination of the skull and other parts of the skeleton. Determining the ancestry of a victim can help law enforcement officials determine the identity of an unknown corpse. Certain common traits can be found in the facial features of the skulls of individuals that share the same ancestry. The human skull has the greatest number of these unique traits.

Some skull characteristics are more common in some ancestral groups than in others. To use three general ancestral groups is common practice: Negroid, Mongoloid, and Caucasoid. However, in the past more than twenty groups have been used.

1. Negroid – from the Spanish word meaning “black”; includes African, Caribbean, and African-American ancestry
2. Mongoloid – from the word Mongolian; includes those Chinese, Japanese, Inuit and Native ancestry
3. Caucasoid – referred to as “white-skinned” or of European descent; originally from the Caucasus region found between the Black Sea and the Caspian Sea; includes Europeans, East Indians, Pakistanis, and Arabs.

The determination of ancestry from skeletal remains is controversial because only a few skull characteristics are unique to one particular ancestral group. In addition, the assessment of ancestry from skeletal remains is not highly reliable because populations are so intermixed today. Consequently, to determine ancestry with any degree of certainty is difficult; thus, forensic anthropologists tend to make suggestions rather than conclusions about which ancestral group may be evident from the skeletal remains they are examining.

Comparison of Cranial Features

Several cranial features have been found to be distinctive in various ancestries. Of primary significance are two regions of the human skull: the orbits and the nasal region. The skull has two orbits that house the eyeballs. The nasal region is the area in and around the nose.

Negroid Ancestry: Cranial Features

Skull of an Individual of Negroid Ancestry

- Image Source: Courtesy the University of Utah Health Sciences Center Osteointeractive website

An individual with Negroid ancestry is more likely to have orbits that are rectangular in shape and a nasal border that is guttered. Additionally, the space between the eyes and nose (interorbital area) tends to be wider than in other groups.

Caucasoid Ancestry: Cranial Features

Skull of an Individual of Caucasoid Ancestry

- Image Source: Courtesy of the University of Utah Health Sciences Center Osteointeractive website

An individual with Caucasoid ancestry tends to have orbits that are sloped. Another distinct feature of Caucasoid individuals is the prominent nasal spine and steepled nasals.

Mongoloid Ancestry: Cranial Features

Skull of an Individual of Mongoloid Ancestry

- Image Source: Courtesy of the University of Utah Health Sciences Center Osteointeractive website

An individual with Mongoloid ancestry tends to have round orbits. Often the base of the nasal area of mongoloid individuals is flared meaning that it appears to widen.

Clues in human bones can help determine the sex of skeletal remains. This is important because it helps establish the identity of the deceased individual. By assessing multiple characteristics in a skeleton, it is possible to estimate the sex of a person. However, in some cases the sex of a person cannot be determined easily because of human variation. The most important and reliable part of the skeleton for determining a person’s sex is the pelvis. The skull may also be used, but variation in skulls may produce conflicting results.

Human Female Pelvis

Human Male Pelvis

- Image Source: Courtesy Features of Selected Bones website, ©David B. Fankhauser, Ph.D., Professor of Biology and Chemistry, University of Cincinnati Clermont College

The most obvious difference between the human male and female skeletons is the pelvic region. Numerous features of the female pelvis distinguish it from the male pelvis; however, in general, the female pelvis appears shorter and wider than the male pelvis. In addition, the pelvic region of the male is usually larger and more rugged than the smaller and slighter female pelvic region.

Femurs from a Human Female (left) and a Human Male (right)

- Image Source: Courtesy the University of Utah Health Sciences Center Osteointeractive website

In general, males tend to be more muscular than females. Therefore, the muscle attachment sites and weight-bearing surfaces on male limb bones tend to be larger and more pronounced. Notice in the above photograph that the upper leg bone (femur) of the male (right) has a number of large ridges where the muscles attach while the female femur does not appear to have these ridges.

Human Skulls: Male and Female

- Image Source: Courtesy the University of Utah Health Sciences Center Osteointeractive website

The human skull differs in several distinct ways in males and females. The above photograph shows two extreme examples of cranial sex differences.

• The supraorbital(above the eyes) ridges in the forehead of a female tend to be slight (gracile) and small while the supraorbital ridges of a male tend to be extreme.
• Below the eyes in a male skull are pronounced ridges to which the facial muscles attach. The ridges below the eyes in a female skull tend to be slighter.
• The chin of the male is often square and angular while the chin of the female is often more curved and round.
• On average, the teeth of males tend to be larger than the teeth of females.

Related Experiment (Optional Activity)

Anthropometric Analysis: Body Size Comparison of Males and Females

Purpose: To compare and contrast the measurements of various body regions of human males and females

Materials:

• tape measure or metre stick or ruler
• calculator
• graph paper
• 4 to 6 male volunteers
• 4 to 6 female volunteers

Procedure:

1. Take measurements of various body parts of at least 8 to 12 different people – at least four being female and at least four being male. (Include yourself in one of these two groups.) This may be challenging, but try to have all your volunteers of a similar age. If your volunteers are under age 18, choose those within an age range of 2 years. If your volunteers are over the age of 18, choose an age range of 5 to 10 years.

1. Use your tape measure, metre stick, or ruler to measure each of the following lengths on each of your test subjects:
   
   
   • hip to sole of foot (cm)
   • length of foot (cm)
   • overall height (cm)
   • length of hand (cm)
   • head circumference at forehead (cm)
   • shoulder to longest finger (cm)

1. Record all these measurements in the observation charts provided.

1. Create a bar graph using the data collected by placing the average skeletal measurements on the x-axis and distance (cm) on the y-axis.

1. Conclude by answering the related lab inquiry questions.

Observation Chart #1

Measurements of Various Body Regions of MALE Subjects

(all measurements in centimetres)

Click Here for a printable version of this chart.

Observation Chart #2

Measurements of Various Body Regions of FEMALE Subjects

(all measurements in centimetres)

Click Here for a printable version of this chart.

Graph Paper

Click Here for a printable version of this graph paper.

Lab Inquiry Questions:

• What specific body regions had similar measurement averages on both male and female test subjects?
  Read Answer

• What specific body regions had different measurement averages on both male and female test subjects?
  Read Answer

Dr. Bradley Adams: Forensic anthropologist for the city of New York.

- Source: Kambiz Kamrani. anthropology.net.

When a forensic anthropologist begins examining remains for trauma, he or she looks for fractures in the bone (for example, simple, compound, or comminuted). A fracture is simply a break in the bone, and there are many different types of fractures. The type of bone fracture depends on the direction from which force is applied. Five directions of force cause bone fractures: compression, shearing, bending, torsion, and tension.

1. Compression - a force that pushes inward from the end of a bone. Fracture lines will often be numerous, wide-reaching, and tend to radiate from the point of impact. This type of force is most often applied to the skull. The shape of the displaced bone will likely match the instrument used to create the wound. Example: aircraft-related spinal injuries.

2. Bending - the most common type of force that causes traumatic injuries. This type of force impacts a bone at a right angle causing a triangular break usually through its cross section. A bending force tends to cause fracture lines at the point of impact or on the side opposite from the break. Usually complete breaks or fractures occur in adults; in children, infractions or ‘green-stick’ fractures occur.

   The most common traumatic fracture caused by a bending force is a parry fracture of the ulna (the thinner of the two forearm bones). This type of fractures results when a person holds out his or her arms in self-defence, and the impact causes inward displacement of the bone. Parry fractures are often seen in accidents in which a car bumper has hit a person’s shins or in deaths involving a violent struggle in which the victim has tried to defend him or herself.

3. Shearing - one end of a bone is held stationary while the other end of the bone is bent. When a shearing force is applied, a linear shearing type of fracture occurs. It is usually caused by a person attempting to stop him or herself from falling. Hence, these injuries usually occur in accidents rather than homicides or suicides. Shearing forces are also created through a blow from a large instrument or object. Shearing forces can occur when a victim is dismembered using a sharp instrument (such as a saw). Shearing force injuries usually involve damage to large surface areas of bone.

4. Torsion - twisting forces occurring most often in accidents. One end of a bone is held stationary while the other end is twisted in some way. These types of forces occur often in accidents such as skiing or biking and in forensic cases such as child abuse.

5. Tension - a force that pulls on the long axis of a bone causing it to break. Tension forces most often cause dislocation of bone, but if the force is strong enough, a portion of bone may break away. This type of bone injury characteristically involves few fracture lines and occurs most often in accidents rather than violent deaths.

1. Blunt Force Trauma - an injury caused by a blow from a large instrument or object with a flat or round surface, which damages a wide surface area of the bone. The resulting injury usually involves bone compression, bending, and shearing forces over a large area. The fracture wounds tend to be simple unless excessive force is applied. Excessive force causes comminuted fractures during which many bone fragments are produced.

   Any weapon used as a club can cause blunt force trauma (such as bat, hammer, boot, rock, or brick). Such trauma can also result from falling or being pushed onto a hard surface. Blunt force trauma typically occurs during car, train, or plane

   Blunt trauma to right of skull

   Massive blunt trauma to
   back of skull

    

    

   

    

   - Source: Julie R. Angel (University of New Mexico-Albuquerque, Maxwell Museum of Anthropology
   and State of New Mexico, Office of Medical Investigator), published in Steven N. Beyers. Introduction to Forensic Anthropology: A Textbook (p. 305). Allyn & Bacon (2002).

2. Projectile Trauma - an injury caused by a blow from a heavy moving sharp object. The types of projectiles causing this type of trauma include bullets, arrows, and spears. The injury usually appears to begin small but becomes wider as the projectile passes through the bone. These types of wounds cause the complete displacement of bone with radiating fracture lines from the point of impact. The type of force produced by this type of trauma is usually a compression force, but some weapons can cause a bending force.

   

    

    

    

    

   - Image Source: Julie R. Angel (University of New Mexico-Albuquerque, Maxwell Museum of Anthropology and State of New Mexico, Office of Medical Investigator), published in Steven N. Beyers. Introduction to Forensic Anthropology: A Textbook (p. 305). Allyn & Bacon (2002).

3. Sharp Force Trauma - an injury caused by a compression or shearing force applied towards a narrow focus. When the force is perpendicular, puncture wounds appear in the bone. If the force is applied at an angle, grazing cut marks are evident in the bone. Complete fractures of bone can occur when the weapon used is a chopping type of instrument (such as an axe). Incomplete bone infraction occurs when the weapon used is a cutting type of instrument (such as a knife).

   Sharp Force Trauma to the Scapula, caused by a Knife

   

   - Image Source: Courtesy Julie R. Angel (University of New Mexico-Albuquerque, Maxwell Museum of Anthropology and State of New Mexico, Office of Medical Investigator), published in Steven N. Beyers. Introduction to Forensic Anthropology: A Textbook (p. 319). Allyn & Bacon (2002).

4. Death by Strangulation - a cause of death suspected when the hyoid (or hyoid bone) is damaged. The hyoid bone covers the voice box (larynx) in the neck. The hyoid bone is a free-floating C-shaped structure of three fused bones. In 8.0% of deaths caused by suicidal hanging, the hyoid bone appears fractured; in 34% of strangulation deaths, fractured hyoids have been observed. Thus, if a forensic anthropologist observes a fractured hyoid bone and no direct evidence suggests that death was by suicide (such as a noose around neck), the inference is made that the evidence is consistent with a death caused by strangulation.

   For a forensic anthropologist to conclude from the remains of a young child that strangulation has occurred is difficult because the three bones of the hyoid have fused in only 7.0% of humans under the age of 20. (See photographs below.)

   Adult Hyoid Bone

   Immature Hyoid Bone
   (< 20 years of age)

    

    

   

    

    

   - Image Source: Courtesy Julie R. Angel (University of New Mexico-Albuquerque, Maxwell Museum of Anthropology and State of New Mexico, Office of Medical Investigator), published in Steven N. Beyers. Introduction to Forensic Anthropology: A Textbook (p. 323). Allyn & Bacon (2002).

- Image Source: crimelibrary.com

Forensic anthropology played a pivotal role in the investigation of one of America’s most notorious serial killers – John Wayne Gacy. Forensic anthropology and other forensic methods helped to identify twenty-two of Gacy’s thirty-three victims. Because only skeletal remains were available for many of Gacy’s victims, forensic anthropology was used to determine exactly how they were murdered.

In 1978, a fifteen-year-old boy named Robert Piest was reported missing by his mother. She had come to pick up Robert from the pharmacy where he worked part-time. Robert had told her that he was going outside to talk to a man who had offered him another part-time job. After three hours of waiting for Robert, Mrs. Piest contacted the local police.

The man who had offered Robert the part-time job was a local contractor named John Wayne Gacy. When police went to Gacy’s house to ask about the whereabouts of Robert Piest, Gacy denied having seen Robert. He told them he was unable to talk to them as there was a recent death in his family and that he had funeral details to arrange. Police asked Gacy to come to the police station later that day. Gacy was questioned several hours later, and he continued to deny having seen Robert Piest. A background check of Gacy revealed that he had a criminal record for sexually assaulting a teenager and that he was awaiting trial for another sexual assault. This led police to obtain a search warrant for Gacy’s house.

In December 1978 when police initially conducted a search of Gacy’s house, they discovered a strong stench in the crawl space below his house. However, the ground in the crawl space looked untouched, so the police initially assumed the smell to be of sewage. Police did find numerous suspicious items in Gacy’s house including two school graduation rings, marijuana, handcuffs, two driver’s licences from two unknown males, police badges, and several articles of teenage boy clothing. In the trunk of one of Gacy’s vehicles, hair matching Robert Piest’s was found.

Finally, after an intense investigation, police discovered that one of the graduation rings found at Gacy's house belonged to a teenager who had disappeared a year earlier. They also discovered that three of Gacy’s former employees had mysteriously disappeared within the last 5 years.

All of this evidence finally led Gacy to confess to police that he did kill someone; however, he initially claimed it had been in self-defence. Gacy told police they could find the body under his garage. Police did find a body under the garage and began finding numerous remains under the crawl space of Gacy’s house. Gacy then confessed to killing Robert Piest and more than thirty other young men.

The search for bodies at Gacy’s house was set up much like an archaeological dig site because the excavation had to be done carefully to preserve the decomposing remains and to keep the remains organized because some of the bodies were piled on top of each other. On the first day of the search, two bodies were found in the crawl space. As time passed, twenty-six more bodies were discovered beneath the crawl space. Some victims were buried so close together that it was hypothesized that they were probably killed or buried at the same time. Gacy told police that on several occasions he had killed more than one person in a day.

During the demolition of Gacy’s property, the body of a young man was discovered preserved in the concrete of Gacy’s patio. Another body was discovered under the recreation room of his house. By the end of December 1978, police removed twenty-nine bodies from Gacy's property. By the spring of 1979, police were able to connect four young male victims found in a local river to Gacy. Gacy confessed he disposed of the bodies in the river because he ran out of room in his crawl space and he had been experiencing back problems from digging the graves in the small crawl space. Fifteen-year-old, Robert Piest was one of the victims found in the local river. Like many of Gacy’s victims, Robert had been sexually assaulted and suffocated after paper towels had been lodged in his throat.

Dr. Clyde Snow, a forensic anthropologist, was hired by police to help identify the victims removed from Gacy’s property. Dr. Snow used missing person reports to help him identify the unknown remains. For example, he identified one set of remains found at Gacy’s property as David Talsma using information from his missing persons report. In December 1977, nineteen-year-old David was reported missing. Records showed that David had fractured his left arm as a child. One set of remains from Gacy’s property showed evidence of a fractured left arm that had healed. Also, the height of the remains matched David Talsma’s height. The last observation that Dr. Snow used to identify these unknown remains was the fact that the left arm was several millimetres longer than the right arm and that the left scapula was bevelled. Both of these observations enabled Dr. Snow to conclude that the remains belonged to a left-handed victim. David Talsma was left-handed.

In the end, investigators used forensic anthropology techniques and dental records to identify all but nine of Gacy’s victims. Gacy was found guilty and convicted of thirty-three murders in 1980. After a long legal battle that he lost, John Wayne Gacy was executed by lethal injection in 1994.

Related Case Study Questions

1. Why was forensic anthropology used in the John Wayne Gacy criminal case?
   Read Answer
   
2. What specific case brought John Wayne Gacy to the attention of police?
   Read Answer
3. Why was the search for bodies at Gacy’s house set up like an archaeological dig site?
   Read Answer
4. In the end, how many of Gacy’s victims were identified with the help of forensic anthropology?
   Read Answer

Defining Forensic Entomology

Forensic entomology is the application of knowledge about insect infestation to the decomposition of human remains from a crime scene. Forensic entomology is a useful technique that can help to determine the time of death, whether the corpse was moved after death, and even the cause of death.

Insects play an important role in our environment because they help to recycle organic matter. Insects consume and decompose dead animals including other insects, dead plant matter, and organism waste (such as feces and urine).

Regardless of the environment, the weather conditions, or the landscape, insects will infest and consume any type of dead organism including humans. Thus, insects are considered carrion feeders, organisms that consume dead organisms. Interestingly, forensic entomologists have found that different insect species infest and colonize a dead body at predictable rates and in predictable sequential order. This process is known as insect succession.

Insect succession upon dead remains occurs in a predictable fashion because different insects thrive on different parts of the body. For example, flies prefer to feed upon fresh moist body tissue while some beetles feed only upon flesh near bone. Consequently, these beetles tend to colonize a dead body much later than flies because bone is normally exposed after several days or more of decomposition. Other beetle species consume mainly blowfly eggs, so they are not found until after blowflies have laid their eggs upon a body. These observations about insect feeding habits help forensic entomologists estimate how long human remains have been left in a particular environment.

Insects can be used to determine a useful estimate of the time since death. They often appear on a corpse within minutes of death, and insect growth and succession are predictable. Consequently, determination of the age of the insects and observation of the type of insects that have colonized a body can lead to an estimate of the time since death.

As a dead body begins to decay, it starts to smell and insects are attracted to this smell. After insects arrive upon dead remains, they begin to feed, and later lay their eggs on the body. In general, insects lay their eggs shortly after they arrive to feed on a corpse. Depending on the temperature and humidity, most insect eggs hatch and the new insects feed upon the corpse within two days of the initial infestation. Therefore, the calculation of the age of these insects can lead to an estimation of the time since death.

Forensic entomologists consider other variables before they estimate the time since death of human remains. Variables that affect the rate of decomposition of a dead body include temperature, sun exposure, time of day, time of year, and whether the corpse was left in soil or water.

The Initial Infestation of Human Remains

Photograph of a Blowfly

- Source: Courtesy Department of Entomology,
University of Nebraska-Lincoln, and Jim Kalisch UNL Entomology

When insects invade human remains, they begin to feed on blood or exposed flesh on the body surface. Regardless of the environment or climate, the most common type of insect to first infest a corpse are blowflies and/or flesh flies. Blowflies and flesh flies play the most dominant role in the decomposition of dead bodies. Usually within moments of their arrival, the female flies begin to lay their eggs in enclosed, moist areas such as open wounds or body openings such as the nose, eyes, ears, mouth, anus, penis, and vagina.

After one to two days, depending on the fly species, the eggs hatch into small larvae. Blowfly larvae are white, have a worm-like shape, and are commonly called maggots. Maggots grow quickly. In two to five days, they can grow from 5 mm to 17 mm in length. During this time of rapid growth, maggots very actively feed on dead tissue. After the maggots go through three larval stages, which take 5 to 7 days, they change into dark-coloured pupae.

Blowfly Maggots

- Source: Courtesy Department of Entomology,
University of Nebraska-Lincoln, and Leon Higley UNL Entomology

Pupae continue to feed on the remains by moving around the body to find more dead tissue to consume. After this active feeding period, the pupae leave the body to find a safe place to shed their outer pupal cases (moult) and become mature flies . This change from pupae to mature flies occurs in a predictable period and is similar to the metamorphosis of caterpillars into butterflies. After a total of approximately 20 to 26 days, the majority of flies leave the body because little flesh remains to feed upon, there competition from other invading insects has increased, and the body has begun to dry due to a decrease in body fluids. Therefore, if no flies are found upon a dead body, but empty pupal cases are found, the person in question has likely been dead longer than 3 weeks. However, the exact time depends on the fly species and the temperature of the surroundings. Warmer temperatures cause faster egg and pupae maturation.

Photograph of Various Beetles

After blowflies and/or flesh flies have left dead remains, usually various types of beetle species are the dominant types of insects found on a corpse. Beetles tend to feed upon mummified tissue. Mummified tissue includes cartilage and other body parts that contain little or no blood or body fluids. The types of beetles that colonize a dead body depend on the geographic area in which it has been left. If the body is left undisturbed and the weather conditions are favourable, beetles will feed upon the body until only the skeleton remains.

The Effects of Weather Conditions upon Insect Infestation

In Canada, insects are most active during the spring, summer, and early fall because of the milder temperatures during these seasons. Thus, it is easier for forensic entomologists to assist in forensic investigations during these milder seasons.

During Canadian winters, a forensic entomologist has difficulty predicting the time since death because insects are not active during this cold season. As well, a body dumped before the winter or during the winter is often covered by snow and not found until the snow has melted in the spring. Then, a forensic entomologist may try to determine whether the death occurred during the winter or before the winter. A death has likely occurred before the winter when dead insect eggs, larvae, pupae, or adults are found in or on the body. By analyzing these dead insects and estimating when they died using meteorological records, time since death can be estimated. Absence of signs of insect infestation likely indicates that the victim’s body was deposited during the winter.

To find and convict a killer, it is often important to determine both when and how a victim died. The sites of blowfly or flesh fly infestation on a corpse may help to determine the cause of death or at least help in the reconstruction of events prior to death. Insect remains on a body can also be tested for foreign substances (such as drugs or toxins).

Usually, flies lay their eggs in the openings of the corpse, such as nose, eyes, ears, mouth, anus, and penis or vagina. Interestingly, forensic entomologists have found that flies tend to lay their eggs more often in the openings of the facial region than in the openings of the anogenital region (that is anus and penis or vagina). However, if a victim has been sexually assaulted prior to death and suffered from bleeding in the anogenital region during the attack, flies will likely infest these areas more than other body openings. Therefore, evidence of heavy fly colonization in the anogenital region of a body is evidence that a sex crime may have occurred.

Flies tend to lay their eggs in enclosed, moist locations such as body openings or open wounds. When heavy infestation of eggs and/or maggots are found in an area of the body where there is no apparent body opening (such as arms or legs), investigators may assume that trauma (such as a knife or bullet wound) has occurred at this site.

Not all homicide victims die from traumatic injuries. Some die of drug overdose or poisoning. Drugs and poisons can be traced in the blood, urine, stomach contents, hair, and nails of a victim’s body. The hair and nails of the dead do not decompose as quickly as the blood, urine, and stomach contents; therefore, they are reliable sites for testing for these deadly substances. These drugs and poisons can also be detected in the maggots and pupae that are found on human remains. Testing maggots and pupae for drugs and poisons is especially useful if the hair and nails of a victim are not found with the remains because various body parts are deposited in different locations or because certain body parts are consumed by an animal.

Using Forensic Entomology to Determine if a Body has been Moved after Death

In some forensic cases, the movement of the body may be traced using insects. If insects found upon a corpse are not native to the surroundings in which the body was found, it may be assumed that the individual was moved from one location to another. Insect parts or whole insects found upon evidence related to a homicide may be traced to their native locations. For example, insect parts or whole insects may be found within the interior of a suspect vehicle or in the tire treads of a suspect vehicle. These insects then could be traced by a forensic entomologist to a specific geographic location that could lead to a determination of where the suspect has been or where a victim’s body may be found.

The determination of the specific types of insect species found on human remains may also help to determine if a body has been moved or if it has remained in one location. For example, some fly species prefer to lay their eggs in warm, sunny places while other flies prefer to lay their eggs in shade. Some fly species are more common in cities while other fly species are found mostly in rural areas.

Pig Remains Infested by Blowflies

- Source: Courtesy Department of Entomology,
University of Nebraska-Lincoln, and Jim Kalisch, UNL Entomology

The information about insect colonization patterns or insect succession that forensic entomologists use to investigate homicide cases comes from data collected from scientific research studies. Because insect species and weather conditions vary from one climate to the next, research data from one geographic area (such as mixed boreal forest) cannot be applied to another geographic area (such as subtropical). Therefore, forensic entomologists use insect succession data that comes from the same geographic region as the region in which the body was found. Because homicide victims can be found in various geographic regions, numerous scientific research studies about insect succession must be completed to help forensic entomologists assist in criminal investigations. In 1996, the Canadian Police Research Centre (CPRC) began establishing a database that contains information about insect succession from each of the major biogeoclimatic zones in Canada.

One of the CPRC insect succession studies was completed in 1999 near Edmonton by Dr. Gail Anderson and Dr. Owen Beattie. The Edmonton area was chosen for this study because it is located within the mixed boreal forest zone, the biogeoclimatic zone with the highest human population in Alberta.

Instead of using human remains, pig carcasses from local farms and slaughterhouses were used to model humans. Pigs were used because their overall size and the position of their internal organs are similar to the human body. In another attempt to simulate how human remains may be found in forensic cases, some of the pig carcasses were dressed in human clothing. To prevent small animals such a coyotes from eating the dead pigs, they were covered with wire mesh.

To simulate further various conditions in which human remains may be found in a forensic investigation, the pig remains were studied in eight different types of conditions: sun, shade, spring and summer, autumn and winter, partially buried, and completely buried.

Sun vs. Shade

When forensic entomologists compared the decomposition of several pig carcasses left in the sun with several pig carcasses left in the shade, the following were discovered:

• The same type of fly species and beetle species invaded the dead bodies left in the sun and shade. However, decomposition by insect succession took longer in the shade.

• Masses of maggots infested the head first in the dead bodies left in both the sun and shade.

• A greater number and a greater variety of insects were found upon the pig carcasses left in the sun compared to the pig carcasses in the shade.

Spring and Summer vs. Autumn and Winter

When researchers compared the decomposition of several dead pigs during the spring and summer with several dead pigs during the autumn and winter, the following were observed:

• The most abundant fly species to infest the pigs in the spring/summer was a type of blowfly known as Protophormia terraenovae. The most abundant species of fly to infest the pigs in the autumn/winter were ‘cool weather flies’ also known as Phormia regina.

• It took 6 days before fly eggs were laid upon the dead bodies observed in the autumn whereas flies laid their eggs upon the dead bodies within 24 hours during the spring and summer.

• In the dead bodies studied during the autumn, fly eggs did not mature into maggots likely because of an early snowfall that caused cold temperatures and high humidity. In contrast, fly eggs consistently matured into maggot masses in the dead bodies studied in the spring and summer.

Partially Buried vs. Completely Buried

Some of the pig bodies were left on the ground and partially buried under tree branches while several other pig bodies were completely buried in graves 20-30 cm deep. When scientists compared the decomposition of the partially buried pigs with the decomposition of the completely buried pigs, the following were noted:

• In the partially buried bodies, blowfly colonization followed by beetle infestation occurred in a predictable fashion. In the buried bodies, beetle infestation was predominant.

• After 15 days, decay had occurred in the face and head region of the partially buried bodies while decay was isolated to only the feet in the completely buried bodies.

• After 30 days, most of the flesh and skin on the partially buried bodies was gone and skeletal remains were visible. After 30 days, the flesh and skin was still present in the buried bodies, but they appeared bloated. Bone was not visible.

• Decomposition caused by insect infestation took longer in the bodies that were completely buried than in the bodies that were only partially buried.

Forensic anthropology and forensic entomology are two unique, specialized fields of forensic science that help law enforcement officials investigate the most tragic of all crimes – unknown deaths. These two fields involve the careful scientific analysis of dead human bodies. Perhaps in an attempt to make their difficult job somewhat easier, forensic anthropologists and forensic entomologists use technical terms to describe the bodies and body parts they analyze. This specialized group of scientists acknowledge and respect the evidence they handle as important because each corpse is an individual person.

This lesson focuses on three criminal case studies that involve forensic anthropology evidence and forensic entomology evidence. Two of the crime case studies are based on actual events in history:

• The Bones That Were Worth a Thousand Words
• The Girl, the Army Sergeant, and The Bugs

The third crime case study is fictional and is entitled The Farmhouse Murder.

You are expected to answer related questions about these case studies in your assignment booklet.

- Source: Hoover Institution Stanford Report website (March 3, 2004)
Landhuis, Esther: Finger points to new evidence: Remains may not be Romanovs

Background Information

The Romanovs were the royal family that reigned in the largest country in the world, Russia, for 305 years. When the Communist party came into power in 1917, Czar Nicholas II was forced to give up his throne. He and his family were placed under house arrest in Siberia. On the night of July 17, 1918, the former Czar, his wife, their five children, and four royal attendants were executed by communist soldiers known as the Bolsheviks.

The Executions

The Romanovs and their royal attendants were taken into the basement of the house in which they were being detained. In thirty minutes, more than a dozen soldiers killed the entire group of eleven victims. To prevent identification, each body was stripped of its clothing, and the soldiers used their rifle butts to smash each face. Then the bodies were thrown into a truck and taken to a remote area. Before the victims were thrown down an abandoned mineshaft, the bodies were soaked in sulfuric acid and burned. In another attempt to prevent identification of the bodies, several grenades were detonated in the mineshaft.

When rumours of the burial site spread to a nearby town, several high-ranking soldiers went back secretly, removed the bodies from the mineshaft, and loaded them into a truck. They intended to move the bodies to another undisclosed site; however, their truck broke down. Consequently, the soldiers buried most of the bodies in a concealed pit near an abandoned cart track.

Initially, the Communist government tried to cover the murders by announcing the family had mysteriously disappeared. Eventually, the government announced that the former Czar had been executed and that his family had been sent away to another detainment site.

Discovery of the Bodies

After 74 years, the skeletal remains of the Romanovs and their royal attendants were excavated in 1991. Two of the bodies were not found in this mass burial site. It was assumed but not confirmed that these were left in the mineshaft. To confirm the identity of the nine bodies found, bone samples were sent to Britain and the United States for DNA analysis. Czaritsa Aleksandra was the granddaughter of Queen Victoria of England so investigators used mitochondrial DNA analysis to link her skeleton and the skeletons of three of her daughters to another member of the British Royal Family, Prince Phillip. Mitochondrial DNA also linked the body of one of the adult males to Czar Nicolai II's brother. Finally, nuclear DNA connected these two adults and the three young women to each other. The remaining four skeleltons were unrelated to the royal family.

Teams of Russian and American forensic anthropologists analyzing the skeletal remains were able to determine the age and sex of each skeleton. Both teams of scientists determined that nine victims likely died from multiple bullet wounds to the head and body and from multiple bayonet wounds to the body.

Famed American forensic anthropologist, Dr. William Maples, identified each of the skeletal remains. He identified the Romanov daughters by looking at the maturation of their pelvic bones and wisdom teeth (third molars). Nicholas was identified by looking at his face shape, poor teeth, height, and his pelvis that was deformed because he had spent many hours on horseback. Maples was able to identify Nicholas’ wife and one of the royal attendants, their personal physician, by their unique dental work. The physician had worn a dental plate and Nicholas’ wife had expensive platinum crowns. The royal maid was identified by the fact she had worn joints due to her many years of hard work. The royal cook was identified because of his unique brow shape, and the royal footman was identified by his age and height. Dr. Maples determined that the two missing skeletons were those of Nicholas’ only son, Alexei, and his youngest daughter, Anastasia.

Conclusion

Genetic testing by geneticists and skeletal analysis by forensic anthropologists led to the assumption that the remains were authentic. A funeral was held for the Romanovs and their attendants in 1998, and the bodies were laid to rest with State honours. Some branches of the Russian Orthodox Church even recognized the Romanovs as saints.

Background Information

On June 4th, 2002, the partially clad body of a young female was found beside a rural highway in northwestern United States. She was identified subsequently as a fourteen-year-old prostitute. Her brother reported her missing approximately four days prior to the discovery of her body. The main suspect was a thirty-year-old male army sergeant. Witnesses said on May 31st she had had been seen alive in the company of this suspect. An accurate estimate of time of death was crucial to establishing a possible link between the suspect and the victim at the time death occurred.

Insect Evidence

An autopsy revealed that the victim had died of multiple head and neck wounds inflicted by a heavy sharp object. These were the only wounds found upon the victim’s body. Numerous blowfly eggs, maggots, and adult blowflies were observed and collected from in and around the victim's wounds. Numerous photographs were taken of the crime scene, the surrounding terrain, and the corpse. These photographs included close-ups of the adult blowflies and blowfly maggots present at the time the body was discovered.

Climatological data, daily temperatures, incidence of rainfall, cloud cover, wind speed and direction, and relative humidity were obtained from a government weather station located a short distance from where the victim was found. Based on this total array of evidence, entomologists determined that the first blowflies to colonize the body had arrived on May 31st. The insect evidence indicated that the victim had been dead for four days prior to the discovery of her body.

Conclusion

Based on this evidence, the army sergeant with whom the victim had last been seen alive was arrested and charged with first-degree murder. After his arrest, he admitted to having murdered the victim by striking her six to eight times with a small hatchet on May 31st. The 30-year old suspect pleaded guilty to the murder charge, and he was sentenced to life in prison without parole.

A Small Hatchet

Background Information

A group of teenagers accidentally found the fully clothed skeletal remains of an unknown adult in the cellar of an old, abandoned farmhouse. When police arrived at the scene, they found no identification on or near the body; however, the pink skirt and high heels found with the remains suggest that the victim was a female.

Old, Abandoned Farmhouse

Bone Evidence

Very little flesh was found with the skeletal remains of the victim. A forensic anthropologist noted that the orbits of the eyes of the victim were round and the supraorbital ridges of the forehead were slight. Other observations of the skull included that the base of the nasal area was flared and that the canine teeth were small. The pelvis was relatively wide and flat.

Example Photograph of Pelvis Found

Skeletal Trauma

The hyoid bone of the victim had numerous fractures within it, and several parry fractures were observed in both of the victim’s lower arm bones.

Insect Evidence

Several types of active beetle colonies were found upon the skeleton. No blowflies were present; however, numerous blowfly pupae membranes were found in the skull and in the anogenital area.