MURDER MOST BRUTAL PART 2

Question 4

Other than examining the dental aspects provided as evidence, what other ways can the victims be identified?

The methods of identifying victims is summarized in a flow chart below :-

A- DNA

1. Anatomical location for DNA in tooth

The teeth differ in form and size but have similar histological structure. The dentin is a connective tissue that forms the major structural axis of the tooth and is hardly exposed to the oral environment. The dentin on the crown of the tooth is covered by enamel. The enamel has an ectodermic origin and is an extremely mineralized tissue. Furthermore, it is an acellular and avascular structure without nerves. The root dentin is covered by the cement, another type of calcified connective tissue. Soft tissue within coronal and radicular pulp chamber consists of odontoblasts, fibroblasts, endothelial cells, peripheral nerve, undifferentiated mesenchymal cells and nucleated components of blood which are rich sources of DNA. Other less frequently used anatomical locations of DNA includes, odontoblastic process that extend into dentinal tubules, soft tissue within accessory canals, cellular cementum, adherent bone and periodontal ligament fibres

2. Method used to amplify the amount of DNA extracted

PCR is used to amplify the amount of DNA material available, so that sufficient quantity is available to carry our DNA analysis. To carry out the reaction special enzyme and DNA primers are required. These primers are like probes with known constant sections of DNA but not labeled. They are designed to known constant sections of DNA at the ends of variable region to be amplified. The principle of PCR is that the DNA is capable of duplicating itself. This is done by unwinding the strands of DNA and each strand acts as a template for synthesis of new strand. By PCR technique we can amplify specific DNA segments dependent on the primer employed. The standard PCR reaction runs through 30 cycles in a couple of hours which results in amplification of original DNA by over 109 times. The DNA found can be genomic (found in the nucleus) and mtDNA (in the mitochondria). The teeth are an excellent source of genomic and mtDNA because PCR analyses allow comparing the collected postmortem samples to known antemortem samples or parental DNA. Main advantage of mtDNA is the high number of copies per cell (from hundreds to thousands of organelles).

(Schematic photograph showing replication of DNA by PCR)

3. Identifying individuals by sequencing mitochondrial DNA from teeth

Mitochondrial DNA (mtDNA) was extracted from teeth stored from 3 months to 20 years, including teeth from the semi-skeletonized remains of a murder victim which had been buried for 10 months. Tooth donors and/or their maternal relatives provided blood or buccal cells, from which mtDNA was also extracted. Enzymatic amplification and direct sequencing of roughly 650 nucleotides from two highly polymorphic regions of mtDNA yielded identical sequences for each comparison of tooth and fresh DNA. Our results suggest that teeth provide an excellent source for high molecular weight mtDNA that can be valuable for extending the time in which decomposed human remains can be genetically identified.

4. Stabilization of DNA in a tooth

Extraction of DNA from the human body remains a difficult task and depends upon numerous environmental factors and extraction procedures. Experience has shown that DNA from hard tissues like bone and teeth are most stable even after putrefaction of bodies (decomposition of dead bodies). The pulp produced the strongest PCR amplification signals, while dentin and cementum signals were very similar to each other.

B-CCTV Footage

Investigators could probably look out for any closed-circuit television (CCTV) security monitoring systems installed at any street corners or even any public buildings nearby the crime scene. Thorough examination of the videos captured within the estimated time range might reveal certain important clues such as possible suspected individuals, vehicles or even the appearance of victims. All the suspected murderers or possible witnesses appeared in the recovered video could be identified and a thorough interrogation should be run on them to obtain any relevant evidences.

C- Mass media

Once the murderer and victims has been confirmed, the mass media should be responsible for alerting the civilians about the breaking news. Newspaper headlines, radio and television broadcast reporting the story of murder should be in detail. Pictures of the murderer can be printed on posters and put at places which is visible to the civilians to warn them. The news from television or newspaper can be posted online for online viewers. Besides that, the news can be further posted on social networking sites such as facebook.

D- Environment/Belongings

Environment

The environment offers many clues that, during the course of a day, we often overlook or take for granted. The dust and dirt that accumulates on skull, mandible, and teeth are able to provide important clues about the crime, as well as the suspect. These minute clues can often point to the criminal's hobbies, occupation, habits and movements and are often helpful in guiding an entire investigation.

 Murder Weapon

In a complex world of weapons, forensic scientists see hundreds of different wounds causes by weapons other than guns. For example, blunt trauma, sharp trauma, asphyxiation, strangulation and assault. All of these forms of murder are brutal and the wounds on the dead body left behind provide vital evidence of the type of weapon used by the criminal.

By measuring the depth, width, gap and shape of dent on skull, we can make several assumption on what weapon did it, at least we know it was not a gun shot or knife stabs. Using all these information, we can search around the park or residential area for suspicious tool which might hit the victim.

Based on the skull evidence, we can narrow down to blunt force trauma.  Deaths resulting from blunt force trauma are some of the most common cases encountered by the practicing forensic pathologist. Blunt force trauma is routinely involved in cases classified as accidents, as well as in cases of suicide and homicide. For instance, almost all transportation fatalities — including those involving motor vehicle collisions, pedestrians being struck by vehicles, airplane crashes, and boating incidents — result from blunt force trauma. Other deaths resulting from blunt force trauma involve jumping or falling from heights, blast injuries, and being struck by a firm object, such as a fist, crowbar, bat, or ball

 But we should not eliminate the possibility which the victim had a trauma accident before which caused the blunt force on the back of the head without causing him dead.

Question 5         

• List the evidences that have been presented to both the doctors. 

Picture 1

As we could see in the 1^st picture, it shows a set of skull with a jaw which bearing a few posterior teeth. One feature we could see from the skull was the zygomatic cheek bone is less prominent as compare to a male’s skull bone. While the lower jaw/mandible on the right shows the 3^rd molar has already been erupted. In both cases, it has a high likelihood that the victim in here could be a female aged more than 20 years old. 

Picture 2

These pictures above show a broken part of the lower right jaw/mandible which also bearing all posterior part of molars, 1^st, 2^nd molars and permanent second premolar. The sharp or a more pronounced edge of the right angle of mandible indicated there would be a higher chance of this particular jaw belongs to a male victim. As for the clean cut edge of the might lead the forensic  team a clue that the male victims encountered a brutal hit on the jaws, leading the jaw fractured into 2 or 3 parts.   

Picture 3

Picture 3 shows a jaw bearing some teeth. Basically most of the teeth of the child’s lower jaw is missing, only 1^st permanent molar, first premolar, canine and  lateral incisor are present.

Presence of 1^st Permanent molar : indicates that the child is at least 6 years of age.

First premolar : indicates that the child is  10-12 years of age
Canine : indicates that the child is  9-10 years of age
Lateral incisors : indicates that the child is  7-8 years of age

• Considering the evidences available up to this point in time, describe in detail how you would go about investigating further, assuming you are Dr. Rudi or Dr. Suria, explaining what you anticipate at each step.

I would continue searching the parameter for body parts or any human remains. So far, only an adult’s skull and jaw as well as other pieces of jaws have been found. More evidence would put us in a better position to conclude anything. I would send a DNA sample from the skull and jaw obtained to the lab for analysis. Possibility of an analysis would depend upon the age of the DNA as available technology and protocols do not allow the analysis of ancient DNA. Evidence should be examined further and data should be recorded in complete and accurate forms. Use a small paintbrush to remove dirt as gently as possible from the skull and jaw structures. Take photographs and place markers for site and direction as well as scale. Keep bones in labeled containers under appropriate conditions. Dental analysis should be conducted where identification of recovered human remains in addition to whole or fragmented bodies is conducted. Dental analysis may also assist in determining gender, age, race, occupation and previous dental history of unidentified human beings. Identification is done by the comparison of ante mortem and post mortem dental records and using the unique features visible on dental radiographs. Ultimately, it can be used to find out the person to whom the teeth belong to. Once the ages of the victims are estimated using dental analysis, forensic science can be used to determine when the victim was killed. Estimated time of death and the date the victims were reported missing can be compared.

In this murder case, the body parts of victim may be severed and hid elsewhere. This hypothesis is estabished due to inability to find any other parts of bones of the body except the skull. Dr. Rudi and Dr. Suria should organise a search party the find the remaining part of body. Clothes may be found on the body. Fingerprints is searched on the victim’s body/clothes, which can lead us closer to the murderer. Besides that, the clothes is searched for any blood stains of the murderer(since there may be struggling of victim before death), further leading us closer to the murderer’s identity.(blood stains can be cultured and DNA matching with the suspects DNA)

Search on weapons for murder must be conducted. From part 1, Dr. Suria mentioned about ‘blunt force at the back of the head’, indicates that there might be trauma caused by weapons. The might be fingerprints and blood stains(from victim and murderer) and hair entangled (from victim) on the weapon, which leads to confirmation of the victim and murderer.

Then, we should cross check the list against missing adults and one child who were reported a few months of each other. This, in addition of the remaining information obtained, can be used to identify the victims.