FORENSIC ARCHAEOLOGY

Forensic archaeology is the use of archaeological methods by experts to exhume crimes scenes, including bodies. These forensic experts are trained to methodically excavate and record their dig. They document the recovery of artifacts (evidence), such as human remains, weapons, and other buried items, that may be relevant to the criminal event. Forensic archaeologists will often work in concert with other forensic experts in DNA, physical matching, forensic entomology, and forensic odontology in the examination of evidence.⁶

Important Terminology

Context—An artifact’s context includes its provenience, exactly where the object was found (horizontally and vertically) in the site; its association in terms of its relationship and positioning with other objects.¹

Continuity– The continuity of evidence is often referred to as the ‘chain of evidence’ which is simple terms is the way the evidence has been handled from the moment that it is found, seized, or produced to the point that it is presented in court as an exhibit. Where the item was placed after it was seized. Continuity of evidence is the documentation of all information, step by step chronologically related to the collected evidence connected with a particular case maintained properly without breaking the chain of custody from the crime scene to the courtroom. From the first responders to the end – users of the information, all entire personnel should have an adequate understanding of the forensic process, like identification, recovery, collection, preservation, transportation, and proper documentation to maintain the chain of custody.⁵

Chain of Custody– It is the written records of all of the individuals who maintained unbroken control over the items of evidence. The chain of custody must account for the seizure, storage, transfer and condition of the evidence. It establishes the proof that the items of evidence collected at the crime scene is the same evidence that is being presented in a court of law. The chain of custody is absolutely necessary for admissible evidence in court.⁵

To Safeguard the Chain of Custody:

• Limit the number of individuals handling evidence.⁵
• Confirm that all names, identification numbers, and dates are listed on the chain of custody documents.⁵
• Ensure that all evidence packaging is properly sealed and marked prior to submission.⁵
• Obtain signed or otherwise secure receipts upon transfer of evidence.⁵

Matrix– natural materials such as sediments surrounding and enclosing the object in place.¹

In situ, which is Latin for “still, “meaning they are in their original place of deposition.¹

Law of Horizontality– the assumption that soil layers accumulate on top of one another.¹

Law of Superposition– the assumption that younger soils are found above older soils, which form the basis of stratigraphic dating or stratigraphy, in which archaeologists construct a relative chronological sequence of the soil layers from earliest (at the bottom) to youngest (at the top).¹

Types of Recovery Scenes

Recovery scenes are where human remains have been located. These can also be called crime scenes, however, not all recovery scenes are crime scenes, and this term is only applicable if a crime has been committed. There are generally four types of recovery scenes: buried remains, surface remains, burned remains, and those that have been submerged underwater.²

Buried or interred remains are those that were placed underground. You would assume that all such remains were placed in a grave by a perpetrator, however, there are natural forces such as rockslides and water that can cover the remains with debris. Buried remains are more of a challenge to find than surface remains as they will not be visible to searchers.²

Remains that have been left on the surface, meaning there was no attempt to bury the remains, maybe be found in the same position and location as they fell. This is unlikely though because there are various forces that can shift and even carry off some of the bones. These forces include: water, gravity, wind, and animals. When remains have been shifted from their original position they are called a surface scatter.²

Burned remains are also generally surface remains, although they can be buried by debris. These are some of the most difficult recovery scenes as remains tend to be highly fragmented and there maybe safety concerns associated with the scene itself.²

Remains that are found within bodies of water are called submerged. These remains can be found on the bottom of a body of water, floating in between the bottom and the surface, or on the surface itself. Remains have been found in various bodies of water, including, but not limited to ponds, rivers, oceans, swamps, and lakes.²

Buried Remains

To expose and recover buried remains excavation of a site is required.

Excavation is not an easy task. More importantly, however, it is a destructive technique since the grave is not renewable. If an error is made during the excavation process, the forensic anthropologists cannot undo that work or even redo it—what’s been dug up stays dug up. It is critical that nondestructive methods are used whenever possible and that excavations are done systematically when scientists are ready to recover the remains.¹

Excavating

Perhaps the first truly scientific excavations, directed by specific questions about the past, in the United States were conducted by Thomas Jefferson in 1784 in Virginia when he dug a trench in a burial mound to discover who had made it and why. This excavation allowed Jefferson to collect data that pointed to Native Americans as the mound builders and indicated that they had used the mound on multiple occasions.¹

Excavations can be small in scale, such as the 1-meter by 1-meter test pits or large in scale, such as entire grave complexes. The scale of excavation units is selected based on the crime scene itself.¹

Once it is determined that an excavation is needed, they must tackle several steps.¹ A preliminary important step is to survey the site so that any surface findings (including human skeletal remains) are collected, sorted, mapped and inventoried. In addition, the site should be documented by means of written descriptions, a sketch map, and photography.⁴

The next step is to map the site and create a grid system that they base on the coordinates of a fixed point, the datum, which is used for all of their future measurements. The datum typically is a prominent geographic feature of the site such as a large boulder, building, or fence post to which a GPS point can be affixed. Using an immovable object as the datum point allows future researchers who excavate in the same area to refer to earlier work.¹ If there is a geodetic benchmark in the area that can also be used as a datum. A Geodetic benchmarks are used by surveyors and mark the elevation or a specific reference point on the earth’s surface.² The location of the datum should be recorded using a Global Positioning System (GPS). In case no datum is readily available, one can be constructed (for example, using concrete pillars). A subdatum is located closer to the remains at a specified distance from the datum. The grid should extend beyond the excavation area in order to capture all features. ⁴ The gird should be constructed by first creating the y and x axis lines which meet at the gird datum. Where these two lines meet should form a right angle.²  This can be confirmed by using the Pythagorean Theorem: a2 + b2 =c2.¹  Gird stakes can then be placed at different intervals depending the size of the excavation and scene.² The grid can be subdivided into square units and numbered in a systematic manner.⁴ Additionally, to the large grid of the excavation area, micro-grids may be used to divide each of the square units.⁴

You have probably seen photographs of excavations in which the “holes” are square rather than round. Why does the shape of the hole matter? By digging a square hole, archaeologists can easily calculate how many bones and other evidence are present per unit—in this case, a measure of volume. Since a square is made of up two equally sized right triangles, archaeologists ensure that the holes they dig are perfectly square using the Pythagorean Theorem: a2 + b2 =c2 . Using this calculation when the initial grid lines of the map are drawn and when individual units are established will ensure that each unit is a perfect square.¹

After the site has been mapped, an excavation can begin.¹

Trenching involves cutting a narrow trench across the area of interest with the aim of identifying the boundaries of the burial site based on soil differences and human or other remains. The use of several closely spaced trenches is advised so that the location and size of the burial site are accurately identified. An alternative method is area or surface stripping. This method involves removing surface soil layers until the boundaries of the burial site are identified by soil changes or other characteristics. In our experience, area stripping generally works better for burial grounds, since the compartmentalization caused by trenching complicates the subsequent excavation. Once defined, the burial site outline should be photographed, measured, and described in notes before further excavation ensues.⁴ A site plan should be produced to depict all features in relation to each other and in relation to the datum. The plan should be at a scale that will effectively capture all the key information: the standard for most burials is a ratio of 1:10 cm; however, a scale of 1:20 cm may be best for drawing multiple burials, and a scale of 1:50 cm or even 1:100 cm may be used for drawing widely scattered remains. Alternatively, or additionally, site photographs may be printed and used for on-site notes, while tablets can also be employed in site documentation. Additional photographs and brief notes should be taken. It is important that any materials identified from different grid squares are kept separate.⁴

Forensic Anthropologists are systematic when they excavate since, as mentioned earlier, data from the site cannot be renewed.¹ This is why when graves are excavated, they are done so layer by layer.² Two excavation methods are commonly employed: the stratigraphic method and the arbitrary level method (pedestal method).⁴

Stratigraphic Excavation

This method emphasizes the need to define stratigraphy in a grave in order to understand the chronological sequence of the events that led to its formation. The walls are preserved so that the grave contents are kept in situ, provided that there are no health and safety concerns. Stratigraphic layers are excavated successively and the layer from which each find originates is recorded. It is important to stress that skeletal (and other) remains found within the same stratigraphic deposit share an association; however, there may be no relationship between remains in different layers. Therefore, when examining disarticulated skeletons, one should first look for possible matches within the same layer. The identification of individual stratigraphic units is sometimes clear, but at other times it can be very difficult. Evidence that may assist in the identification of distinct layers includes bulks of soil between deposits of remains, the orientation of the bodies and/or the presence of different types of deposits (primary vs. secondary) in successive layers. In addition, the input of experienced archaeologists, who are familiar with the general area and stratigraphy, can be invaluable. The weaknesses of stratigraphic excavation include insufficient water drainage, limited access to the skeletal remains due to the maintenance of the burial walls, difficulties in identifying stratigraphic units, and considerable time investment. The advantages include the three dimensional reconstruction of the grave and the chronological reconstruction of the events that formed the burial.⁴

Arbitrary Level Excavation

In arbitrary level excavation, soil is removed in successive levels of specific depth (e.g., 0.05m, 0.10m, 0.20m), without considering the existence of stratigraphic layers. Any findings are usually left upon a soil pedestal until the excavation of the level has been completed and then they are documented and removed, together with the pedestal. In cases of mass burials, to gain better access to the remains, trenches are often dug perimetrically, destroying the grave walls. The advantages include better control of soil removal, easier access to the remains, and more effective water drainage. The problems with this method include the destruction and non-consideration of stratigraphic layers within the grave, the lack of stratigraphic origin for the different findings, the mixing of strata and artifacts from the grave structure and natural strata through which the grave was dug, and the incomplete documentation of the grave cut. A possible compromise between the two excavation approaches would be to follow the stratigraphic method at least until reaching the remains and then, if absolutely necessary, to destroy the pit walls in order to facilitate excavation/recovery of the bones. Nonetheless, this may create problems if there are more than one “floor” layers in the grave and you must continue digging lower.⁴

Irrespective of the excavation method adopted, soil removal should take place at sub-layers 2-5cm deep. In the stratigraphic method these sub-layers will follow the stratigraphic layers, whereas in the arbitrary level excavation, they will not take stratigraphy into account. By using sub-layers, each bone layer can be revealed and recorded more accurately. Any skeletal remains should be exposed at the same level. If the bones continue deeper than the selected layer, layer documentation should be completed before digging deeper. In addition, skeletal remains should be collected and inventoried by grid square and by micro-grid location per square in order to achieve maximum degree of spatial control within each burial context. Each soil type encountered and its composition should be described in the field notes.⁴

Burial Documentation

Once the remains per layer have been exposed, they should be mapped on graph paper, photographed, and documented with notes prior to their collection. Using standardized recording forms is highly advisable. The position of each bone must be documented (graphically and numerically) on a plan using the reference grid.⁴ Forensic anthropologists typically take measurements of the depth of excavation across the entire square to ensure it was excavated to precisely the same depth throughout. This is important as the surface, where excavation begins, is typically naturally uneven, but the bottom of the strata level should be flat. And because the ground is rarely level, a plumb bob or line level is often used when taking the measurements.¹ As stated above, the scale of the plan will depend on the size of the burial site and the detail required, but the most common scales are 1:10 cm and 1:20 cm. A simple way of making accurate plans is by obtaining a photograph of each bone layer and superimposing tracing paper over the photograph to outline each bone. An alternative or rather complementary approach is to individually number all bones and tag them on digital photos. The orientation of the skeletons should be mentioned by stating the skull first; for example, a north-south orientation indicates that the skull is at the north.

Drawing to scale using grid-system mapping

Other Mapping Methods

Triangulation is used to document the location of evidence in relation to two reference points, one of which is the datum. This is done by running a line from each reference point, one at a time, to the piece of evidence and determining the angle that has been created by this line. The length between these reference points must also be measured.²

Trilateration is used to document the location of evidence in relation to two reference points, one of which is the datum. This is done by running a line from each reference point, one at a time, to the piece of evidence and measuring how far those points are from that piece of evidence. The length between these reference points must also be measured.²

Azimuth Control Point Mapping is similar to the above methods because measurements are taken of both the angle and the distance from the datum to a piece of evidence. This is done by affixing a azimuth board, a 0-360˚ board, to the datum and placing it in such a way that the zero on the board points directly north. Lines are run from the center of the board to evidence scattered around the board. The distance is than measured and the angle determined.²

Baseline/offset Control Point Mapping can be quickly used to document surface scatter. This is accomplished by running a string from the datum to another point so it bisects the evidence. Then the distance from the string to the evidence is measured at a right angle. Then a second measurement must be taken from the datum to the point where the last measurement began on the line. Every measurement taken above the line should be denoted as positive and everything below the line should be denoted as negative.²

GPS or the Global Positioning System determines the location of a point on the earth’s surface by measuring the angle and the time it takes for a radio signal to travel from a satellite to a GPS receiver. This is a simple and relatively inexpensive way to document the location of a recovery scene. Tree GPS points should be taken at every scene.²

Total station uses a theodolite to quickly take measurements of a site and construct a 3-D Map. However, theodolites require special training and are expensive.²

Photography of the Recovery Scene

After the preliminary observation of the recovery scene, it should be recorded carefully by photography/sketching. Both videography and still photographs of the recovery scene should be taken systemically. The photographs of any physical evidence are essential for the examination and assessment of the importance of the evidence. The overall, medium, and close-up views of the scene as well as the evidence should be photographed successively with suitable scale or other size determination devices whenever applicable. The photographs should be taken from eye level when feasible so that they exhibit the scene, as it would be observed by the normal view. The physical clues should be photographed in place before its collection and packaging using a size determination device, if necessary.⁵ One photograph documents the unit’s location on the grid system and the depth of the layer excavated using a sign and an arrow pointing north to make it easy to orient the unit and identify its location later.¹

Photographs of the overall view of each layer should be taken, with north point and scale clearly visible, followed by closeup images of the bones in each grid square. Close-up images should also document any noteworthy features (e.g. unusual burial position, pathological lesions). In addition, it may be useful to obtain record shots from a specific fixed point in order to document each step of the excavation. Once the excavation is completed, these photographs can be viewed in reverse order and show how the grave deposit was formed and reconstruct the environment of decomposition of the body. Whenever the necessary equipment is available, the grave may be documented by 3D laser scanning or photogrammetry. Contrary to drawings and photographs, which provide a 2D image of individual stratigraphic layers and profiles, such techniques visualize the 3D structure of the archaeological site. The data obtained from scanners and photogrammetry can easily be combined and produce detailed excavation plans as well as virtual animations, where different contextual information may be combined to reconstruct the site.⁴

Sketching of the Scene of Crime

Sketch is the whole picture of the crime scene which show the distribution of the evidentiary clue at the crime scene. The sketch is convenient to appreciate the evidence at crime scene, the nature of the crime and the modus operandi of the commission of the crime. The sketch provides ideal, simple and easily intelligible mode to understand the place of occurrence. Supplement the other mode of recording the crime scene by videography, photography and written inspection report.⁵

Stratigraphy

Stratigraphy, the study of layers of soil, is an important component of all excavations. Stratigraphic data assist forensic anthropologists in putting the grave into context; the data provide a relative way to date the site and its contents and can provide some contextual clues about natural formation processes that occurred after the site was abandoned.¹

For stratigraphy to be used scientifically, the researcher must make two assumptions, both based on the work of Nicolaus Steno, a geologist from the seventeenth century. The first assumption is that soils accumulate in layers that are laid down parallel to the Earth’s surface. This is known as the Law of Horizontality. The second assumption, the Law of Superposition, assumes that older soils will typically (but not always) be found below younger soils (that the old stuff will be on the bottom). These two assumptions allow scientists using stratigraphy in their work to understand how the soils accumulated and to use the layers to “tell time.”¹

Screening

As excavating proceeds, the material removed is sorted using a screen. The screening method used varies with the circumstances, including the type of matrix or soil and the condition of remains or other evidence they expect to uncover. Typically, screens consist of a wooden frame with window screening material affixed to the bottom. The soil is put into the screening box, and workers sift the soil through the screen, which leaves larger chunks and objects behind. The screens’ dimensions vary based on the evidence of interest to the anthropologist.¹ The size of the screen will depend upon the soil type, but as a general rule, a 2mm sieve works well in most contexts. If possible, a double sieving process can be followed whereby the soil goes through a 4-5mm sieve initially and then through a 2mm sieve. All findings, including human skeletal remains, should be sorted, and allocated an inventory number. In addition, all findings should be accompanied by an indication that they came from screening.⁴

When forensic anthropologists are especially interested in locating small plant remains, they can use a water screening process called flotation, in which the excavated material is flushed through a water sieve that allows the lighter materials to float to the surface, making them easy to recover. Water screening is also sometimes used for larger objects encased in a matrix that is primarily clay or some other dense or wet soil. In that case, hoses or buckets of water are used to wash the dirt off the objects. Decisions about whether to use wet or dry screening methods and the size of the screen to use have a dramatic impact on the kinds of materials that can be recovered and the condition in which they are retrieved. Small bones will be lost to time if the screen is too large, and pressure from a water hose can damage or even destroy bones. So, these seemingly small decisions are a critical part of planning an excavation.¹

During the screening process, workers sift the materials and pull out evidence and bones. Each item is preliminarily put in a bag clearly marked with its provenience (three-dimensional coordinate information, including its layer and its specific position relative to the surface—the depth at which it was found). A evidence catalog will also be created that records everything that was uncovered in the field. Each piece of evidence is given an evidence number that corresponds to a listing of it in the evidence catalog. The items are then placed in bags with the provenience information written on the outside of the bag and, usually, on a small tag placed inside the bag. This seeming duplication of information is critical in case the information on the bag rubs off or something happens to the number on the artifact.¹

Documentation of the Recovery Scene

The purpose of the observation and documentation of the recovery scene is to make a note of the location of potential evidence and to mentally prepare and make an outline of how the crime scene will be examined. The crime scene conditions should be carefully observed and transient details, such as weather, temperature, or other disturbances should be recorded. Photography and videography may be used for the documentation of crime scene conditions. It can provide a better perspective on the crime scene layout. Photography and videography should begin with a general overview of the recovery scene and the surrounding area, and it will cover the recovery scene using wide-angle, close-up (long, middle, and close-up range) shots to show the shape, size, and position of the evidence and its relevance to the crime scene.⁵

Bone Collection

To minimize damage to the skeletal remains, these should be removed from the site as soon as possible after their excavation. Before excavated bone is bagged, it must be cleaned as much as possible from adherent soil. The one exception is the cranium: soil removed from the cranial cavity in the field may result in the cranial bones of younger individuals (with unfused sutures) coming apart making laboratory reconstruction difficult, cleaning the nasal apertures and the eye orbits may destroy delicate bones, while cleaning the area around the maxilla and mandible may result in the loss of loose teeth. In case there is no time to clean the bones on site, these should be wrapped in acid-free paper and then foil to maintain their structure before they are transported to the lab. Paper bags should be used and the site name/location, identification number, excavation date, the name of the person who recovered the bone or bones, and skeletal remains contained in each bag should be clearly marked using permanent ink.^1/2/4 When multiple bags are kept in a box, heavier and more robust bones should be placed at the bottom. Bubble wrap may be used for extra protection, if necessary. Special care is needed when neonatal remains, poorly preserved or pathological bone is bagged. Such bone should be wrapped in acid-free paper and then bagged and boxed.⁴

Taking bone/tooth samples for later DNA and isotope analysis during bone collection from the field should minimize contamination variables; however, it will preclude the macroscopic study of the sampled elements. Any samples obtained, should be registered at the evidence log and documented on-site photographically and with notes.⁴

Final Clean Up

Once all skeletal remains have been lifted, the remaining soil in the grave should be removed and screened to recover any remaining elements, and a final photograph should be taken. To ensure that no deeper deposits are present, even if you are certain you have reached the bottom of the burial, it is advisable to remove the soil stratum below the estimated floor of the deposit.⁴

Fire Scene

Cremation has been a funerary practice in many different cultures since prehistory, while bodies may also be exposed to (lower) degrees of heat during mortuary practices such as cleansing fires. Besides funerary practices, a human body may be exposed to fire as a result of different events, such as car or aircraft accidents, bombings, natural disasters, homicides and suicides. In forensic contexts fire can also be used to destroy evidence and hinder the identification of the deceased. For these reasons, any anthropologist working in circumstances where burned skeletal remains may be encountered should possess a general understanding of the physical and biochemical alterations bone and teeth undergo when exposed to varying degrees of heat. The study of burned human remains poses special challenges compared to the anthropological study of non-thermally altered bones as exposure to heat produces macroscopic color changes, shrinkage, fragmentation, and warping, as well as microscopic structural and chemical changes to bones. To ensure that these alterations are precisely analyzed and interpreted in their respective forensic context requires a specific approach in the field and in the laboratory.³

Fire Dynamics

Fire is an oxidation reaction that generates heat and light. There are three requirements in order to make a fire (the so-called ‘fire triangle’): heat, oxygen, and fuel. Heat involves raising the temperature of an object to the lowest temperature at which it will sustain combustion. The amount of oxygen must be such that can sustain combustion. Finally, the fuel refers to the combustible materials that are present and capable of sustaining the fire. The best ‘fuel’ in the human body is subcutaneous fat. The available amount and interaction of the parts of the fire triangle will determine the duration and intensity of the fire and, therefore, its impact on a body.³

Even when subjected to extreme burning, human bodies cannot be completely destroyed. In general, the effects of fire on human tissue vary based on the proximity of the body to the fire, the temperature reached, and the duration of exposure to the fire. It should be remembered that during the thermal exposure of a body, these parameters alter as temperature, heat and ventilation conditions can fluctuate dramatically. In addition, the preincarnation condition of bone, that is, the preservation of blood, marrow, moisture, and fat, also influences heat-induced alterations. The temperature reached during heat exposure depends on the amount of oxygen available, the size and volume of the body, the clothing and other layers surrounding the body, and others. Soft tissues surrounding the bones have a protective effect as they limit the transfer of heat and restrict oxygen supply to the skeleton. This protective effect depends upon the thickness of soft tissues, thus bones surrounded by thinner layers of soft tissues will be exposed to higher temperatures and levels of oxygen before bones protected by thicker, soft tissue layers, which will take longer to be affected by the fire.³

A typical outcome of heat-induced shrinkage of muscles, tendons and ligaments is the arrangement of the body in the so-called ‘pugilistic posture’ or fetal position.^2/3 The ‘pugilistic posture’ will provide further protection for some anatomical regions, hence the pattern described in the previous paragraph may not be observed. However, the sequence of skeletal fire alteration is affected by many parameters, such as the position of the body on the fire, the pre-burning condition of the body, the size of the individual, prior pathological conditions, and many others.³

Heat-Induced Bone Transformation Stages

The first stage, dehydration, is characterized by the breakage of the hydroxyl bonds in hydroxyapatite crystals and water loss, leading to subsequent weight reduction and fracturing. Using scanning electron microscope (SEM) analysis, dehydration is characterized by bubbles in the external lamellae and cracking. Dehydration occurs approximately between 100˚C and 600˚C. The second stage, decomposition, takes place at 300-800˚C. During this stage, organic components decompose and this results in color change, weight loss, reduction in mechanical strength, and changes in porosity. SEM analysis shows an increase in the diameter of the crystals and the lacunae but bone structure is still recognizable. In the third stage, inversion, there is an increase in crystal size, the carbonates are removed and magnesium is released, causing additional weight loss. Under SEM, cracks are wider and the matrix becomes increasingly more homogeneous, while lacunae become less visible. The inversion stage occurs between 500˚C and 1100˚C. The last stage, fusion, is characterized by the melting and coalescence of the crystal matrix. An increase in crystal size can be observed, and considerable bone dimensional reduction and an increase in mechanical strength take place.³

Carbonization

Organic materials contain high proportions of carbon atoms and experience carbonization when exposed to intense heat. During heating, complex organic molecules break down and elements, such as oxygen and hydrogen, are either freed into the atmosphere or combine with other elements, while structural carbon remains. Since naturally occurring carbon is black in color, carbonized bone is also black.³

Calcination

During calcination, the freed carbon from organic molecules is combined with oxygen and forms carbon dioxide (CO2) or carbon monoxide (CO). Subsequently, it is released into the atmosphere. The remaining bone is comprised of inorganic components, thus its color is white because this is the natural color of hydroxyapatite. Fracturing, shrinkage, and warping accompany calcination.³

Commercial Cremations Versus Outdoors Pyres

Given the importance of the environment in which fire exposure takes place, it is relevant to outline how modern cremations compare to outdoors pyres. Modern commercial cremations take place in gas-fired ovens, where the main chamber is lined with heat-resistant refractory bricks. The body is placed inside a body bag, a cardboard box, or a wooden coffin. The temperature is typically 870°C–980°C and the average duration 2–2.5 hours. Afterwards, the burned remains are pulverized to reduce further their volume, leaving little diagnostic bone. By contrast, in outdoors pyres, which require human intervention and constant heat sources, most of the heat is lost to the atmosphere, a constant external heat source is necessary, and the temperature cannot stay uniform throughout the process. A further complicating factor is the wind, the strength and directionality of which will affect heat distribution and temperature maxima. In addition, the heat is directed to the body only from below, whereas in the cremator heat exposure is multi-directional. Once the main pyre structure burns down, the remains will rest on the hot ash bed, and the cremation may continue for several more hours. Weather conditions play an important role in the duration for which the pyre will burn: strong winds will make the pyre burn faster but unevenly, while rain will reduce the pyre temperature or even extinguish it. The vegetation surrounding the pyre is also important: dry vegetation will increase fire temperature but reduce its duration due to the fast consumption of the fuel; oily vegetation will take longer to ignite and the pyre duration will be prolonged, while with wet vegetation, a fire may not ignite.³

Myth Busting

‘Spontaneous combustion’ and the ‘exploding skull’ are two myths regarding the human body’s response to fire. The former implies the near complete cremation of human bone under unexpected circumstances. Experimental studies have shown that while humans do not spontaneously combust, they are particularly combustible under certain circumstances, such as when bones are osteoporotic. With regard to the ‘exploding skull’, contrary to popular opinion, the cranium does not explode when exposed to prolonged heat. Numerous factors may fracture a burned skull, such as falling debris, the handling of burned remains, the means by which the fire is extinguished, and others, and these external events is what creates the appearance of the exploded skull.³

Filed Procedures

Burned remains may be found in various contexts: on the ground surface, (partially) buried, inside funerary structures, etc. Any field procedure has to be adjusted to the unique challenges posed by each context of recovery and the associated degree of preservation of the remains, the sample size, and the degree of commingling. In some contexts, a confined excavation will be appropriate, while in others, surface surveying will be a necessary first step to document the spread of the remains.³

Burned human remains pose two additional and interconnected challenges compared to unburned remains: fragmentation and identification. Burning can lead to extreme bone fragmentation, which hinders recovery in the field. This extreme fragmentation coupled with the morphological, chemical and structural deformities that characterize burned bone, often renders the differentiation between such bone and other materials difficult. During each of these steps, it is important to describe in detail any features and the stratigraphy, including plan and profile maps, as well as measurements. Any post-depositional disturbance should be recorded in detail as well, while soil samples should be taken, and sample locations should be documented. The excavation, documentation and recovery should continue until undisturbed strata are visible.³

Surface and Submerged Remains

Surface and submerged remains can be documented in the same manner as buried remains. The only difference with surface remains is that they do not have to be excavated. With submerged remains excavation and recovery utilizes the same methods only because they are underwater they must be completed by specially trained divers.²

Conclusion

Crime scene investigation is a very important part of any investigation. It is the meeting point of science, logic and law. Physical evidence includes all objects that may establish or deny that a crime has been committed or link a crime with its perpetrator or victim. Forensic science begins at the crime scene. Here, investigators must identify the evidence for laboratory testing and preserve it properly. The primary duty of the first responding officer is securing the crime scene. Once the scene is secured, the relevant investigators record the crime scene taking photograph, making sketches, and taking notes. The search for physical evidence in a crime scene must be thorough and systematic. Physical evidence can be anything from large too small. Each different item or similar item collected in different places must be placed in a separate bag. Packaging evidence individually prevents damage through contact and prevents cross-contamination. At the time of evidence collection, the chain of custody must be maintained with a record indicating the location of the evidence. Hopefully, this review will help to forensic anthropologists to deal with crime scene evidence.⁵

 

References:

1. Amanda Wolcott Paskey and AnnMarie Beasley Cisneros, Digging into Archaeology: A Brief OER Introduction to Archaeology with Activities (California: Academic Senate for California Community College, 2020). https://asccc-oeri.org/wp-content/uploads/2020/06/OERI-Archaeology_Final_4_29.pdf.

2. Angi M. Christensen, Nicholas V. Passalacqua, and Eric J. Bartelink, Forensic Anthropology: Current Methods and Practice, 2^nd ed. (London: Academic Press, 2019), 184-209. Efthymia Nikita, AN INTRODUCTION TO THE STUDY OF BURNED HUMAN SKELETAL REMAINS Guide No. 4 (The Cyprus Institute Science and Technology in Archaeology and Culture Research Center, 2021), 3-6. https://d1wqtxts1xzle7.cloudfront.net/66384827/Nikita_2021_Burned_remains_STARC_Guide_4-libre.pdf?1618985138=&response-content-disposition=inline%3B+filename%3DAN_INTRODUCTION_TO_THE_STUDY_OF_BURNED_H.pdf&Expires=1678149157&Signature=V3d2u~GoK1t3hObRJujif2d~0U7dcbQqIueyDfP-Z9bQleWMaiHUFVLkNJN1FslN9mLklEcKy-O1HmAamTzuvcctJvE1oXSDVu0yKdmt-Qll-RD8Hu7ME7QWhjEuupbSYiDkl7Rr5gJMTesNELfvB55Ro4pUULb1qo31AE4VFoppvQYh1C4-e4nBOD4i0Bm2tzLkmCaXEUXnY~lnp1orP~3AUWVVm3dSFoxIyEOAqnr8VeDu7eIOKqga-Z1bVmaUR2zo-1eV9L0oMS–qr2HordqvNItjWL0swjB-CPngV61i-bbh5YsEyk7L9rkuyrQdTa8dHnJyXKj7Mk865G5Hw__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA.

3. Efthymia Nikita, Anna Karligkioti & Hannah Lee, EXCAVATION AND STUDY OF COMMINGLED HUMAN SKELETAL REMAINS Guide No. 1 (The Cyprus Institute Science and Technology in Archaeology and Culture Research Center, 2019), 2-9. file:///C:/Users/lbail/Downloads/BASIC_GUIDELINES_FOR_THE_EXCAVATION_AND_STUDY_OF_HUMAN_SKELETAL_REMAINS_GUIDE_1.pdf.

4. Harendra Nath Singh, “Crime Scene Investigation,” International Journal of Science and Research 10 (2021): 644-645, 647. https://d1wqtxts1xzle7.cloudfront.net/74759496/SR211112005543-libre.pdf?1637125126=&response-content-disposition=inline%3B+filename%3DCrime_Scene_Investigation.pdf&Expires=1677977767&Signature=G-nWZ6XfAfJR3mGHUh0tAVLz~fg1UbW7Ey5kLwG-ssw~84THlc86fwc2izMPwzo0W0DT3IXIV5EYQYXeyarci-nzN-Qxoz6ZIfAptAtolahb8vx9TO2YRQkcCmDmFvQYbFdomdYw1QJQ~-hUeCTKdUS1LlIARJrzfPWsmSgVHBYi9mJHscZPcLONl-OEpufFlZeVFEUMV66XeYB9dmohGzIREEIwXtVzHIVLI5Vhy1JwePjz5f2YzuPIDqoDd8faznbNCZyKJ77~nPaGbGWTCjP-MMwygP1-HaluK0zlOL964VB9pCOCahg3IH3qu52mZ35iuDTtZr6~WxjjjxXFJg__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA.

5. Rod Gehl and Darryl Plecas, Introduction to Criminal Investigation: Processes, Practices and Thinking (New Westminster, BC: Justice Institute of British Columbia, 2017). Download this book for free at https://pressbooks.bccampus.ca/criminalinvestigation/ as follows: digital format: on every electronic page print format: on at least one page near the front of the book.