PART II: EVIDENCES AND FURTHER INVESTIGATIONS

EVIDENCES


-A part of a large jaw bearing five teeth;

-A jaw with some teeth still in eruption;

-A piece of jaw bearing 3 posterior teeth.



For the first picture, we can guess that it is a male victim as the ramus is at nearly a right angle and the skull robust. Since the third molar has erupted, he is likely to be older than 17 years old. Since all of his alveolar ridge can be seen and some teeth are in tact, the person is suspected to be not too old of age and isn’t born with missing teeth.

For the second picture, we can guess that it is a male victim as the ramus is at nearly a right angle. The third molar has erupted hence he is likely to be older than 17 years old. The occlusal table is also shallow which may be due to prolonged attrition and there doesn’t seem to be any alveolar process mesial to the first right mandibular molar indicating that it might have been the second premolar might have been extracted. This suggest that the victim is of elderly age but this is however inconclusive.

For the third picture, we can guess that it is a female victim as the chin is pointed. It is also observed that the permanent canine of the female has just erupted implying that she is of 9 to 10 years of age.


With very limited resources of only a few fragments of jaw and no less than a skull, the usual identification means prove to be very restrictive. The methods below would aid further in identification of a victim :





1) Sieving


Retention of soils is a pre-requisite for subsequent sieving (screening) off-site and offers much potential depending upon the questions being asked by the investigation. The types of forensic material that can be recovered through visual sieving that may have been missed during excavation include small durable objects such as buttons, items of jewellery, glass fragments, projectiles, small elements of human remains (e.g. tarsals, phalanges, neonatal bones, nails, etc.), or less durable items such as paper, wrappers or cigarette ends. Survival of the latter items will be more heavily dependent on the soil environment, the time since burial and the level of human decay within the grave
Coarse sieves ( 5-10mm) to recover small items
Smaller sieves ( <1mm) for macro-remains (animal bones, insect, botanical evidence)


Human hair is one the examples of sieved item which has been shown to be a relatively good survivor with a high potential for DNA extraction.


Sieving Methods:
Dry sieve (Outdoor/Laboratory)
Wet Sieve (Outdoor/Laboratory)
Flot (Outdoor/Laboratory)

-soil to be broken down into water and where lighter bodies float to the surface to be floated away and heavier bodies stay in residue in which is then sorted out using the microscope

















2) DNA Profiling Tests




SGM :

It tested six DNA STR regions and a sex-determining marker and had a discriminating power of approximately 1 in 50 million.


Identifiler : 

This test includes the 10 STRs and the sex marker used in SGM with the addition of a further five loci which allow greater discrimination between closely related individuals. Consequently it is extensively used in paternity testing and in the identification of unidentified deceased individuals when reference samples are to be submitted from close family members.


Powerplex16: 

This test includes 13 of the STRs and the sex marker present in Identifiler with the addition of two alternative STRs known to be highly variable between individuals. Consequently it is of use when the further investigation of close family relationships is required.


Y-STRs: 

This test uses STR regions located only on the male Y-chromosome. As females have no Y-chromosome Y-STRs can only be passed on through the male line of a family, hence all male members of the same family line will have the same Y-chromosome and consequently the same Y-STR profile. This test is therefore used to investigate familial relationships where males are thought to be related. This is particularly useful when the relatives in question are not biologically close (e.g. grandfather and grandchild.


Mitochondrial DNA: 

Mitochondria are small organs (‘organelles’) responsible for cellular respiration. They have their own DNA and are present in all cells in large numbers. Mitochondria are inherited maternally; hence all maternally related individuals will have the same mitochondrial profile. This test is therefore used to investigate relationships where individuals are thought to be maternally inherited. In addition, because there are many mitochondria in every cell, mitochondrial profiles can be obtained from degraded samples where nuclear STR DNA testing has failed to produce a profile, but there must either be direct reference samples available from the individuals in question or reference samples from confirmed maternal relatives in order for comparisons to be made.



3) Radiography

Carry out an orthopantomogram(OPG) to get radiography of the mandible. Therefore, we can know the estimated age of the victim by depending on the maturation of crowns and also transparency of roots.

4) Forensic facial reconstruction


By using this method, we can recreate the imaginary face of an individual either into two or three dimensional by using the skull and large jaw found.




5) Radiocarbon-14 dating
We can determine the radiocarbon content in tooth enamel by using radiocarbon-14 dating. This method works on the principle that accumulation of carbon-14 by the body will stop upon death, and will decay at a fixed radioactive decay rate. Therefore, by knowing the carbon-14 content in the deceased and through calculations, the age and year of death of the victim can be estimated.






6) Forensic anthropology

We can determine the gender of the person based on the shape of their shape of their forehead, brow ridges, angle of ramus, and shape of chin as can be seen in the following pictures below

According to part 1, Dr. Rudi mentioned that there is ‘Blunt force on the back of the head’. By looking at the size and shape of the injury of the skull (as used in ballistics forensics), we can approximate the weapon used and try to find evidences of the weapon in the vicinity.

Lastly, by cross-checking the list of missing person in few months back, we can narrow down the scope to only a few suspected victims. Then we can interview their family to find out more information related to the case.