AN321 - FORENSIC OSTEOLOGY
FIELD & LABORATORU MANAGEMENT
OF SKELETONISED REMAINS
The University of Queensland
The laboratory investigation and skeletal identification of badly decomposed or skeletonised human remains depends for its success on the completeness of the material recovered from the crime scene and on the full documentation of the immediate context in which the remains were found.
Much evidence that may be crucial to the establishment of the individual's identity, including the time since death and the reconstruction of the circumstances and events surrounding the disposal of the body, may be missed or lost due to incorrect or inadequate recovery and recording techniques.
It is important to try to determine early in any such investigation, if the remains might be those of a prehistoric or tribal Aborigine. Such a determination will prevent further waste of the investigating team's time and resources and the inadvertent or unnecessary interference with Aboriginal relics. (Macdonald & Ross 1990)
Usually the presence of human skeletal remains is discovered accidentally and reported to the police. They may be found lying in the grass or bush, under a rocky overhang, in a riverbed, washed up on the beach, in a disused or burnt out building, in an abandoned container or vehicle, uncovered by earthworks or soil erosion etc.
Sometimes they are the result of deliberate excavation of a suspected burial site reported by an informant, or of a burial exhumation requested by the Coroner. Human skeletal remains requiring identification have even been recovered from the stomachs of crocodiles and sharks (Wood 1987; Burke 1987; Rathbun & Rathbun 1984).
The gathering of information relative to the identity of the unknown individual begins right from the time of the discovery and reporting of the remains. The initial and immediate primary requirement is for the site to be made secure.
The amount of information that will be available and the recovery methods that should be employed, are dependent upon whether it is a surface find, a burial, or from a watery context. In every case the aim is to recover the maximum evidence with the minimum of damage or disturbance to the remains or their environmental context.
Because of the great possibility of drift of a body in a watery environment before skeletonisation has occurred, little evidence is usually available from the immediate context of skeletal remains found in water. The remains themselves or any container in which they might be located, must be carefully screened for entomological or plant material evidence that might indicate some initial exposure or disposal of the remains on land prior to their immersion in water.
On land, however, much information may be obtained from the surrounding context of a skeletal find.
With skeletal remains found on the surface of the ground, the disposition of the bones may indicate the manner of disposal of the body or the possibility of animal or other postmortem interference with, or damage to the remains. The degree of exposure to the elements and the local microclimatic temperature and humidity, may also prove vital to the establishment of the time since death. Such evidence is not actually preservable and must be recorded and noted at the time of the recovery.
Buildup of vegetation around and through the remains and the association of insect larvae and pupae may provide valuable clues as to the season of disposal and the time elapsed since death. Evidence of the passage of fire over the site, or of the falling of an overhanging branch, rock or other object which might have caused postmortem damage to the bones, could be incorrectly interpreted in the laboratory if the association was not noted directly in the field.
It is important to realise that recovery of information is invariably accompanied by destruction of information and that not all the evidence may be obvious to the field officer at the time of recovery. Therefore record and collect everything that could be important. Accurate and detailed notes, sketches and plenty of photographs are an absolute necessity.
After defining the limits of the crime scene and careful searching, identification and labeling of all exposed bones and artifacts; their exact location and disposition needs to be fully documented and recorded photographically before lifting. This requires careful site reconnaissance and surveying and mapping of the locality, as well as the mapping of all bones and artifacts relative to a fixed datum point.
Scanning the site with a metal detector, and careful sieving of the associated soil to a depth of 8-10cm after lifting of the remains, is required to ensure complete recovery of skeletal fragments, displaced teeth and small artifacts.
Expert knowledge, full documentation, care and patience are the essence of a successful field recovery.
With a burial, the application of basic archaeological techniques should be applied to the recovery process to prevent the inadvertent loss or destruction of important information particularly as to Aboriginality, the time since death, and the method and manner of disposal of the victim.
Adequate recovery procedures include:- site reconnaissance; establishment of a datum point; gridding, surveying and mapping of the burial area; systematic excavation with scanning of each excavation level with metal detectors; complete exposure, recording, photography and systematic lifting of bones and artifacts after recording their three dimensional disposition; careful soil screening to recover small bones, teeth and artifacts; soil profiles to ascertain stratigraphic evidence and details of the burial pit; and selected soil sampling for pH determination and toxicology, or to recover insect remains, pollen samples or other botanical or cultural evidence.
Remains recovered from fire scenes may be so charred, calcined, distorted or fragmented, as to be unrecognizable to the untrained eye. Contrary to popular belief, human bodies rarely are destroyed completely by fire even of the most intense type, nor is the context completely destroyed except perhaps by the inadvertent activity of the fire-scene personnel. According to Wolf (1986 pp13-14), "except under the most extreme circumstances (eg temperatures well above 2500 deg F. for periods of time in excess of 12-18 hours) bodies are seldom if ever totally consumed in fires".
Because the limbs are often burnt off and the skull has frequently disintegrated into many smaller fragments, the charred torso (usually the lower abdominal & pelvic area) is often all that remains. It may not be recognised for what it really is, and may easily be dismissed as normal fire debris. The remains of fire scene victims once located and defined, should be recovered with great care and with the application of the same strict archaeological controls and techniques as for surface or burial recoveries.
The following published articles contain recommended skeletal recovery procedures for surface, burial and fire scene locations: Morse et al (1984), Wolf (1986) and Bass & Birkby (1978). These techniques are summarised in the following tables:
1. Establish site security;
2. Photograph the general locality of the remains;
3. Establish the limits of the crime scene;
4. Clear any vegetation (except trees) to 1-2cm above the soil surface and remove loose surface debris;
5. Establish a datum point and surface grid;
6. Use a metal detector freely and mark all positive findings with wooden markers or
7. Photograph the cleared area and include a scale direction indicator (N->), site
identification and date;
8. Map all exposed objects with description and location;
9. Take general and close up photographs of all bones and artifacts "in situ";
10. Remove skeletal remains and any associated physical evidence in a systematic way;
11. Check bones against a skeletal list to ensure complete recovery;
12. Bag bones in units e.g. L/hand, L/foot etc. and label them with identification number,
location, date and initials;
13. Excavate positive metal detector readings with nonmetal tools;
14. Screen surface dirt within the grid using water pressure and plastic screens with 2-3mm mesh; entomological evidence may be located some distance (meters) from the remains
as insect larvae tend to migrate before pupating.
15. Screen the dirt for 10-15cm under the skeletal remains.
Fire Scene Recovery:
Fire scene victims should be approached in the same way as a surface skeletal find:
1. Establish security;
2. Photographic documentation of the fire;
3. Careful documentation of the location and position of any suspected human remains before removal;
4. "Fogging" of the body locality to achieve cooling down;
5. Grid the locality;
6. Clear the locality surrounding the body;
7. Analyse and document the body in situ;
8. Remove stratigraphically all debris around the remains and subject it to flotation, water
screening and cleaning for recovery of trace evidence (eg calcined bones or teeth);
9. Remove body with extreme care so that further damage is avoided;
10. General fire overhaul should be carried out only after all bodies have been removed;
1. Search techniques - observation of soil contours and variation;
- observation of vegetation patterns;
- use of steel probes;
- use of GP
- use of aerial & infrared photography
- use of cadaver dogs
2. Establish the limits of the crime scene and site security;
3. Clear the vegetation;
4. Establish a datum point and grid the locality;
5. Locate and map all surface evidence and grave boundaries;
6. Photograph all surface evidence and then recover, package and label each specimen with site ID and date;
7. Search the grave area with a metal detector and mark positive readings with wooden markers or flags;
8. Excavate the grave in 5-10cm soil levels;
9. Expose, map and record each piece of new evidence in situ, before lifting, packaging and labeling;
10. Screen all dirt from the grave fill (not from walls) noting soil changes eg pH, colour, grain size etc.;
11. Scan each new level with a metal detector marking all findings as above;
12. Use wooden tools to excavate metal (so they won't mark the metal);
13. Record all evidence, locate on the grid, map and photograph before lifting;
14. Expose the whole skeleton if at all possible before lifting. This may entail the exposure of the skeleton on a soil pedestal;
15. Remove any soft tissue intact by undercutting and placing on a board or blanket;
16. Make an inventory of the bones as they are removed and package them in units;
17. Take soil samples from the grave fill and the abdominal regions of the remains for pH and toxicology;
18. Scan the dirt for 10-15cm below the burial with a metal detector then remove the dirt and screen for loose bones and teeth, cultural artifacts and entomological or other
19. The empty grave should then be cross-sectioned, photographed and drawn to scale to
record its vertical shape.
Packaging, Labeling & Transport.
Once recovered and from whatever source, human remains and artifacts require careful handling, recording, labeling and packaging.
Bones are best wrapped in tissue and placed in labeled paper bags. Plastic bags are not recommended if moisture is present as this promotes the rapid growth of fungus and mould on the remains especially in warm environments. The wrapped bones should then be carefully placed into cardboard boxes or other suitable containers with adequate packing material to prevent further damage or deterioration.
Transport of the remains, artifacts and soil samples back to the laboratory must be carried out in a manner that prevents the possibility of further damage, loss, contamination or interference during transit. The “chain of custody” must be scrupulously maintained and documented, so that the courts can be reassured that any evidence being presented, has not been contaminated or interfered with during storage and transport back to the laboratory.
Bass WM & WH Birkby 1978 "Exhumation: The method could make the difference". FBI Law Enforcement Bulletin 47:6-11
Burke M 1987 "Eaten Alive". Australian Police Journal, Jul-Sept 83-89
Macdonald J & A Ross 1990 "Helping the police with their inquiries: archaeology and politics at Angophora reserve rockshelter, N.S.W.". Archeol Oceania, 25(3):114-121
Morse D, Dailey RC, Stoutamire J & J Duncan 1984 "Forensic Archaeology." in Human Identification. TA Rathbun & JE Buikstra (Eds), CC Thomas, Springfield 53-64
Rathbun TA & BC Rathbun 1984 "Human Remains recovered from a shark's stomach in South Carolina". Journal of Forensic Science 29(1):269-276
Wolf DJ 1986 "Forensic Anthropology Scene Investigations." in Forensic Osteology. KJ Reichs (Ed), CC Thomas Springfield, 3-23
Weldon Paul 2000 “A study of the effects of Crocodile Digestion on Human Compact Bone” BSc. Hons. Thesis, Department of Anatomical Sciences, The University of Queensland.
Wood WB 1987 "Recent fatal crocodile attacks in Northern Australia." Paper delivered at the Australasian and Southwest Pacific Islander Police Medical Officer's Conference, Gold Coast, Queensland
In Queensland, skeletonised human remains are usually forwarded to the forensic osteology laboratory by referral from the forensic pathologist (John Tonge Centre) who has received them from the police.
The remains should always be accompanied by a copy of a completed Form 4 and by detailed documentation relative to the location and manner of discovery and recovery of the material and by photographic records taken at the recovery scene.
On arrival at the osteology laboratory, all specimens must be checked in and receipted in order to maintain continuity of the “chain of evidence”. The date and time of receipt should be recorded together with the number of packets or containers containing the remains, the documentation accompanying the remains, and the name and signature of the delivery person.
A laboratory registration number is allocated. This is in addition to the JTC (Forensic Pathology) PM or SK number.
Cataloguing, Recording & Laying Out of the Remains.
The specimens are then carefully removed from each container or packet, and the contents identified and catalogued.
They are then laid out on an examination bench in approximate anatomical position, and recorded on a skeletal record chart. Any duplication of bones among the remains will most likely be noted at this stage indicating that the remains are derived from more than one individual. Some indications of race, sex and age may also become apparent.
Any animal bones should be identified as such and separated off from the human bones for later specific identification if warranted.
Associated clothing or other cultural artifacts are noted, catalogued and packaged separately for possible follow-up.
Recording includes the filling in of the skeletal record chart, taped and/or written descriptions and notes, labelled diagrams and photographs (both colour slides and prints).
Samples of any associated soft tissue e.g. skin, hair, finger or toe nails, ligament, tendon etc. and associated soil and insect remains are collected, labelled and stored in suitable containers for further analysis.
Following registration, laying out, recording, and sample collection, the specimens may then be washed (with plain tap water) if necessary before being subjected to detailed laboratory examination, investigation and assessment. Washing should take place in a sink with the drain protected by fine mesh to prevent the inadvertant loss of loose teeth, small bones or bone fragments.
Care must be taken not to scratch the bones with hard brushes, dental probes etc during the washing and cleaning process.
The purpose of the laboratory investigations is to assist with identification of the remains, and the determination of the time of death and the events leading to and surrounding the death of the person.
This will require answers to the following questions:
1. Are the remains of animal or human origin?
2. How many individuals are represented?
3. What are the ethnic affinities of the remains?
4. What is the sex?
5. What is the age at death?
6. What is the estimated stature?
7. What injuries are present? Were they incurred pre or post mortem? What caused
8. What pathology or skeletal variants are present in the remains?
9. Can the time since death be determined or estimated from the remains?
10. Is there any evidence of the manner and cause of death?
11. Can a definitive identification be achieved?
LABORATORY TECHNIQUES EMPLOYED IN SKELETAL EXAMINATION.
When carrying out a detailed laboratory examination and assessment of human skeletal remains, some or all of the following laboratory techniques may be used:
1. Gross (naked eye) examination and detailed description of
the bones. This includes:
general condition; completeness; fragmentation; erosion;
colour and discoloration; evidence of weathering;
grease or greasy feel;
adherent soil/sand, vegetation or other matter;
associated insects or insect pupae; termite activity;
obvious pathology, injuries or anomalies
evidence of antemortem or postmortem trauma.
2. Reconstruction of damaged and broken bones.
Use Tarzan's grip, diluted if necessary with acetone.
Glue only two pieces at a time.
Use a sand bath to hold specimens while the glue is hardening.
Often the details of perimortem or postmortem trauma to bones will only become obvious once reconstruction is complete.
Make records of all reconstructions that are carried out.
3. Low power magnification and scanning of each bone
a) magnification (x5 or x10) eg with a maggylamp or hand-lens.
b) using ultraviolet light (for fluorescence characteristics of bone)
4. Direct measurement of bones (osteometry)
- for stature calculation.
- for metrical race and sex determination.
- for possible reconstruction purposes.
- sorting of bones from mixed skeletons.
5. Radiological and microradiological examination
This can be extremely important to individual identification as the detailed
radiological appearance may be able to be matched up with previous medical or
dental radiographic records especially air sinuses and bone trabecular patterns etc.
6. Histological and electron microscopical examination
This may be important in histological age determination and in the distinction of
animal from human bone .
7. Application of statistical formulae or techniques
for sex and race determination/discrimination.
for stature estimation.
8. Chemical analyses of bone
DNA, fluoride, heavy metals, precipitin tests (d/d animal v human).
If teeth or dentures are present then the expert opinion of a forensic dentist should be sought as expeditiously as possible as this evidence alone may be sufficient to establish definitive identity. In the absence of a forensic dentist then the forensic osteologist should make the necessary dental observations and carry out the necessary dental procedures and tests in an attempt to achieve positive identification.
Only after full laboratory assessment and evaluation of any remains have been completed should the process of matching of a missing individual's premortem details (dental and medical records etc) with the postmortem findings be attempted.
Occasionally techniques such as photographic comparisons or videosuperimposition of premortem and postmortem portraits of the head and the cranium will have to be employed to assist with possible identification.
If after all the above procedures are exhausted no record of a missing person fits the gathered evidence then the forensic anthropologist may have to resort to the technique of facial reconstruction and extensive newsmedia publicity in an attempt to stimulate the public's recognition of a missing person. Under no circumstances however should facial reconstructions be relied upon as the only evidence in establishing identity. In all cases they must always be substantiated by additional unequivocal evidence as to positive identification.
Animal or Human?
The determination of whether skeletal remains are of animal or human origin is vital to the decision of whether to proceed with further investigation or not (Angel 1974, Brooks 1975). Correct identification depends on the experience of the examiner and his knowledge of the whole range of normal human skeletal variability both at the gross and histological level.
The availability within forensic anthropology laboratories of skeletal reference collections of known individuals (animal and human) for comparison with the unknown helps to confirm a definite identification.
With specimens of whole bones or major parts of bones, gross morphological comparisons are the most common method of species identification. Radiological appearances also may be helpful in reaching a definitive conclusion (Hoffman 1984).
Foetal and juvenile bones may occasionally be mistaken for those of small domestic or native animals or birds. In these cases the cranial bones provide the best distinguishing features both because of their size relative to the rest of the skeleton and because of the lack of sutural fusion in human foetal material. The absence of growing epiphyses and the overall size and morphology of the bones of the common domestic and native animals and birds helps to distinguish them from juvenile human bones.
Fragmentary, burnt or pathological bones may pose particular problems in identification. In these cases other methods must be employed to assist with the determination of animal or human origin. These methods include microscopic methods as used by Enlow (1966), and Owsley et al (1985) and/or serological (precipitin test) methods as described by Fazekas and Kosa (1978 pp323-349).
How Many Individuals?
Occasionally the skeletons of more than one individual may be present at a recovery site. The determination of how many individuals are actually represented within the recovered collection of bones requires the identification and laying out of each of the bones in their approximate anatomical position. This may occur at the recovery scene but is best carried out in the controlled conditions of the osteology laboratory. It is usually readily apparent to the skilled osteologist if there is any duplication of bones or disagreement in terms of size, age, sex, colour or other physical characteristics.
Angel JL 1974 "Bones can fool people." FBI Law Enforcement Bulletin 43(1):16-20, 30
Brooks ST 1975 "Human or not? A problem in skeletal identification." JFS 20:149-153
Enlow DH 1966 "An evaluation of the use of bone histology in forensic medicine and anthropology." In Studies on the anatomy and function of bones and joints. F.G. Evans (Ed) Springer-Verlag, Berlin 93-112
Fazekas IG & F Kosa 1978 Forensic Foetal Osteology. Akademiai Kiado, Budapest
Hoffman JM 1984 "Identification of nonskeletonized bear paws and human feet." In Human Identification, Rathbun TA & JE Buikstra (Eds). C.C. Thomas Springfield, 96-106
Ousley DW, Mires AM & MS Keith 1985 "Case involving differentiation of deer and human bone fragments." JFS 30:572-578