Wednesday, November 7, 2012

Question 4

Question 4

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

Anthropology Forensics
Anthropology Forensics is the application of osteology in a crime scene and deals with bony remains to identify the victims. Microscopic studies of the bone fragments can help investigators estimate the age, gender, ethnicity and stature of a victim regardless of the size of the bones. For example, findings of osteoporosis may show that the victim is likely to be an aged female. 

Forensic Ballistics/Weaponry Ballistics

Ballistics is also a discipline in forensics which studies on weaponry, mainly firearms and bullets. The conditions of wounds would enable forensic teams to understand the nature of the weapon(s) used. Based on the concept that each weapon has its own unique toolmark, this helps investigators identify the firearm, bullet and cartridge cases. It is interesting because a simple bullet wound can tell why, how and where did the assaulter attack from.  

Criminal Profiling

This method relies on the principle that each criminal will have a certain signature style of executing their crimes. In other words, it is related to psychology forensics which studies the behaviour of criminals. Crimes prosecuted by the same suspected criminal may be analyzed to identify any similarities or repetitive patterns in the criminal's approach. Following the findings, investigators and psychologists work hand-in-hand to predict the criminal's next move. 

Stomach Contents

Following an autopsy of a recently deceased victim, contents inside the stomach may present with surprising findings. Since digestion may take up to 24 hours to complete, the condition of the contents may help in estimating the time of death. Furthermore, the content itself, may also tell if toxins or poisons were ingested purposefully or unintentionally- which will rule out if the deceased died of a homicide or suicide crime. 


Facial reconstruction
The skull provides clues to personal appearance. The brow ridge, the distance between the eye orbits, the shape of the nasal chamber, the shape and projection of the nasal bones, the chin's form, and the overall profile of the facial bones all determine facial features in life.

 In Vancouver, the police did a 3D facial reconstruction of a badly decomposed victim. This has further proven that this method is reliable and applicable in victim identification.

Reconstructed face of an ancient Athenian girl by scientists in Greece

Demonstration of muscles adding as part of skull reconstruction


Fingerprint
Ever since scientists discovered that every person's fingerprints are unique, and police officers realized this singularity could help them catch criminals, fingerprints have been an integral part of the law enforcement process.

Many fingerprints found at crime scenes are not visible. These latent fingerprints, which are often incomplete, are obtained in various ways:

1. Powder such as ninhydrin to dust the surface. The powder sticks to the oily substances on the print making the pattern visible. The print can then be photographed and lifted off the surface by using a tape to which the powder adheres.
2. Fumes of iodine or cyanoacry-late for porous materials such as paper. These fumes readily collect on the oils in the print pattern and can be photographed. 
3. Argon lasers for latent fingerprints. When illuminated by light from an argon laser, a latent print is often quite visible. Visibility under laser light can be enhanced by first dusting the print with a fluorescent fingerprint powder.

demonstration of extract fingerprints

Modern fingerprinting techniques can not only check millions of criminal records simultaneously, but can also match faces, backgrounds and other identifiable characteristics to each perpetrator.

Serology
Body fluids such as blood, semen, saliva, and sweat, all contain serum. Blood is the most common, well-known and perhaps most important evidence in the world of criminal justice today. Bloodstain patterns tell a lot about position and movement during the crime, who struck whom first, in what manner, and how many times.


DNA can be extracted from blood (if white blood cells which always contain a nucleus are present) according to the following steps:
1. Blood samples are collected from the victim, defendant, and crime scene
2. White blood cells are separated from red blood cells
3. DNA is extracted from the nuclei of white blood cells
4. A restrictive enzyme is used to cut fragments of the DNA strand
5. DNA fragments are put into a bed of gel with electrodes at either end
6. Electric current sorts DNA fragments by length
7. An absorbent blotter soaks up the imprint; it is radioactively treated, and an X-ray photograph (called an autoradiograph) is produced.


Gel Electrophoresis 
The gel with UV illumination, theethidium bromide stained DNA glows orange



Hair Analysis
Look at the cuticle and medulla.
  

The presence of hair on weapon can identify it as the weapon used in the crime. Analysts can use hair DNA to identify or eliminate suspects by comparison. Through hairs and keratin, a person's race and age can be estimated. Under microscopic analysis, we can tell which part did the hair originated from as well how whether it was pulled out or a natural phenomenon of hair fall.

Joints and Soft Tissue Analysis
Something surgically implanted in you by a surgeon will have a documented serial number on record. Originally intended to speed recall of defective devices and ensure patient safety, serial numbers are found on implants and prosthetic. This can be used to trace the medical records of the dead body.

Analyzing the feet
There are currently two main forms used for identification.  being from records kept by podiatrist while examining and treating. The second is marks left by objects they have come in contact with the foot like shoes and ground surfaces(footprints). Toe nails can be a way to find DNA also.

Skin
  1. Body marks can be characteristic of an individual.
  2. A scar can come from surgery, an accident, or assault. Scars such as severe acne during youth can leave scars that remain into adult life and may be a helpful identification tool.
  3. A number of individuals have scars from common operations like appendix removal.
  4. The dates of such operations should be in the person’s medical records and the medical examiner will try to relate this to the age of the scar. 
  5. Blisters on the skin made after death don't contain fluid. Blisters obtained when alive contain protein (will solidify when heated in a test tube) but blisters obtained after death don't.
  6. Ligature marks also appear during manual choke holds; this is when the assailant strangles the victim with his or her bare hands. These ligature marks can sometimes be in the exact shape of the fingers that have applied the force to the neck area and it may be possible to extract skin samples for DNA analysis at this time.

Bite Marks

Criminals seem to leave their bite impressions on the skin of their victims, especially in cases of rape, child abuse, and homicide. There are seven types of bite marks which can be classified:
1. hemorrhage - small bleeding spot 
2. abrasion - undamaging mark on skin
3. contusion - ruptured blood vessel, bruise
4. laceration - punctured or torn skin
5. incision - neat puncture of skin
6. avulsion - removal of skin
7. artifact - bitten-off piece of body 

Lung Analysis

Lungs can also be tested by putting them in water 

The extended lungs may sink in:
  • Diseased
  • In children, if they sink, the child is presumed to have been stillborn.
  • Atelectasis 
Due to:
1. Non expansion of lungs due to feeble respiration
2. Complete absorption of air from lungs by blood, if circulation continued after stoppage of respiration
3. More air being expelled from lungs during expiration than what is inhaled
4. Obstruction by an alveolar duct membrane

Unexpanded lungs may float from :
  • Purefactive gases of the putrefield lungs are soft and greenish. Signs of decomposition seen.
  • Artificial inflation : The foetal lungs may be artificially inflated by blowing air through a tube, catheter or cannula passed into the trachea or by mouth-to-mouth method. 
  • For children, if the lungs float, the child is presumed to have breathed.

  • Additional facts!
      
Identification Method
Chances of Failure
1
Comparison of Scalp hair
1 in 4500
2
Anthropometry
(Bertillon’s method)
1 in 268 million
3
Teeth bite marks
1 in 2.5 billion
4
Dactylography(Fingerprints)
1 in 64 billion
5
DNA Fingerprinting
1 in 2 x 1022



1 comments:

Unknown said...

Wow!! loads of info... sure is gonna be useful for solving the crime...
Great job!

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