Analyses of Different Aspects of Forensic Science Areas

2. TERMINOLOGY
Pathology is the study of disease, so forensic pathology is the study of injuries
and/or disease in order to determine the cause of death.
Involves the investigation of sudden, unnatural, unexplained, or violent
deaths.
Typically these are the medical examiners or coroners
A medical examiner who works for the legal system to determine cause of death in
legal cases. They conduct autopsies to determine not only the ultimate cause of
death but also the manner and mode of death.
Answer questions: who is the victim, what injuries are present, when did the
injuries occur, why and how were the injuries produced, and what is the cause of
death

3. BEFORE AN AUTOPSY - A MEDICAL EXAMINER WILL
SEARCH FOR ANY PHYSICAL EVIDENCE ON THE BODY
• Conditional Evidence – lividity, rigor mortis, odors, insects, position, clothing.
• Pattern Evidence – bite marks, imprints, impressions, weapon marks, insertions,
injuries, wounds.
• Biological Evidence – grass, leaves, wood, plants, pollen, flowers, insects, worms,
etc.
• Chemical Evidence – cosmetics, firearms, vehicle-related chemicals, drugs, alcohol,
poisons, ink, oil, cleaning fluids, soil, glass.
• Physiological Evidence – blood, semen, urine, fecal materials, tears, milk, bile,
tissues, bone, hair.

4. DEATH
Cause of Death
• Asphyxiation
– Strangulation
– Drowning
– Fire victim
• Exsanguination - Major blood loss
• Blunt force trauma
• Sharp force trauma
• Chemical trauma
• Heart failure
• Gun Shot
• Decapitation
Manner of Death
• Natural: 80 year old dies of
congestive heart failure
• Homicide: death caused by another
person
• Suicide: death inflicted upon self
• Accidental: unintentional and
without malice, group swimming
and one drowns
• Undetermined: absolute cause not
able to be determined

5. BODY TEMPERATURE
• Normal body temperature is 98.6˚F
• one hour after death, the body cools at a rate
of 0.78°C (1.4°F) per hour. After
• the first 12 hours, the body loses about 0.39°C
(0.7°F) per hour.
• In 24 hours the body is at external
temperature
• Several days after death Putrefaction (bacteria
in the body release gases causing body to
become bloated) occurs and body temp can
rise to 127˚F

6. ESTIMATED TIME OF DEATH
• Rigor Mortis (“rigor” = stiffness, “mortis” = of death): medical condition that
occurs after death and results in the shortening of muscle tissue and the stiffening
of body parts in the position they are in when death occurs.
• Begins ~4 hours after death
• Stiffening of body because of lack of oxygen in muscle cells
• Begins in eyelids and small muscles of jaw, then to neck and rest of body
• Is spread up by increased external temp and slowed down by cooler temp
• Sets in more slowly with overweight individuals
• Sets in more quickly when there has been a violent struggle (uses up energy in
muscles)
• Completely sets in within 12 hours after death and lasts ~36 hours before body
returns to non-rigid state

7. ESTIMATED TIME OF DEATH
• Livor Mortis or lividity: medical condition that occurs after death and results in the
settling of blood in areas of the body closest to the ground.
• Discoloration of skin after death
• Caused by gravity-induced stagnation and settling of red blood cells in small blood
vessels
• Commonly referred to as “lividity”
• Begins immediately after death and lasts for 12 hours.
• Occurs in parts of body closest to ground (gravity!)

8. ESTIMATED TIME OF DEATH
Algor Mortis (“algor” = coldness “Mortis” = of death): postmortem changes that
cause a body to lose heat. Process in which the body continues to cool to room
temperature. 1 – 1.5 degree/hour.
Effects that influence Algor Mortis are:
• Temperature of the surrounding environment
• Type of clothing on the body
• Wetness of the clothing
• Air movement
• Layers of clothing
• Size of the individual

9. AUTOPSY
1. Weight, height, and physical characteristics are documented
2. Body is photographed, x-rayed, and examined with alternate light source (black
light) for stains
3. Distinguishing characteristics – tattoos, scars, birthmarks
4. Clips fingernails and toenails for further analysis
5. If a rape case, swabs are taken of oral, anal, and vaginal cavities
6. Fingerprints and palm prints
7. Y-incision from shoulders down to abdomen
8. Saw collarbone and ribs
9. Internal organs are all removed, weighed, and measured
10. Blood and tissue samples are taken from each organ
11. If necessary, the scalp is peeled back, skull is opened and brain is examined

10. EVIDENCE TO BE COLLECTED AT AUTOPSY
Autopsy: medical dissection and examination of a body in order to determine
the cause of death
• Victim’s clothing
• Fingernail scrapings
• Head and pubic hairs
• Blood (for DNA typing)
• Vaginal, anal, and oral swaps (sex-crimes)
• Recovered bullets / knives from body
• Hand swabs from shooting victims (for GSR analysis)
• Viscera
• Stomach Contents

11. BODY FLUIDS
• Blood, semen, saliva, sweat, and urine can be analyzed to give
investigators information about the crime as well as its victim or the
suspect.
• Chemicals and ultra violet light can be used at a crime scene to find body
fluid evidence. Areas with potential evidence are swabbed, bagged and
collected in vials, which are air tight and have a low risk of cross
contamination.
Examples:
• Vomit and urine can be used to test for alcohol, drugs, and poisons.
• Cigarette butts may contain dried saliva.
• Semen containing sperm is valuable for DNA analysis.
• Blood can provide DNA evidence and blood spatter can provide clues
about the crime.

12. FORENSIC ANTHROPOLOGY
• Recovery, Identification and examination of human skeletal remains and estimate the
time of death.
– Trying to determine origin, sex, approximate age, race and skeletal injury
– May create facial reconstruction
– Identify victims of mass disaster such as plane crash
– Mass Murder (Oklahoma bombing, plane crashes, World Trade)
– Earlier man (Mummies, Iceman, Lindow man)
– Prehistoric Animals (Dinosaurs)
– Bones Tells us many thing:
• Age
• Ethnicity
• Gender
• Height
• Weight
• Build
• Pathologies like old injuries

13. WHAT DO FORENSIC ANTHROPOLOGISTS DO?
Generally, forensic anthropologists DO NOT do any of the following:
• Collect trace evidence (hair, fibers)
• Run DNA tests
• Analyze ballistics or weapon evidence
• Analyze blood spatter
• Conduct autopsies
What a forensic anthropologist does DO to aid in a case:
• Goes to a crime scene to assist in the collection of human remains
• Cleans up the bones so that they may be looked at
• Analyzes skeletal remains to establish the profile of the individual
• Looks at trauma evident on the bones to establish the pathway of a bullet or the
number of stab wounds
• Works with a forensic odontologist (dentist) to match dental records
• Testifies in court about the identity of the individual and/or the injuries that might
be evident in the skeleton

14. AGE DETERMINATION
Most accurate estimations from:
 Teeth
 Epiphyses or growth plates
 Pubic symphysis
 Cranial sutures: the three major cranial sutures appear as distinct lines in
youth and gradually close from the inside out.
Investigators always use an age range because of the variation in people and how
they age. The investigator does not want to eliminate any possibilities for
identification.

15. RACE AND RACE CHARACTERISTICS
Race is difficult to determine from most skeletal remains, especially since pure
races are becoming uncommon. An experienced forensic anthropologist can
generally place skulls into one of three groups:
 Caucasoids—have a long, narrow nasal aperture, a triangular palate, oval
orbits, narrow zygomatic arches and narrow mandibles. European, Middle
Eastern, and Indian descent .
 Negroids—have a wide nasal aperture, a rectangular palate, square orbits, and
more pronounced zygomatic arches. The long bones are longer, have less
curvature and greater density. Negroid—African, Aborigine, and Melanesian
descent
 Mongoloids—have a more rounded nasal aperture, a parabolic palate, rounded
orbits, wide zygomatic arches and more pointed mandibles. Mongoloid—
Asian, Native American and Polynesian descent

17. ESTIMATION OF HEIGHT
The height of a person can be calculated by using the length of certain long bones,
including the femur, tibia, humerus, and radius. Below are the equations to
determine average measurements for both male and female.
(All measurements are in centimeters)
Male Female
femur x 2.23 + 69.08 femur x 2.21 +61.41
tibia x 2.39 + 81.68 tibia x 2.53 + 72.57
humerus x 2.97 + 73.57 humerus x 3.14 + 64.97
radius x 3.65 + 80.40 radius x 3.87 + 73.50

18. FORENSIC ODONTOLOGY
• Provide information about the identification of victims when the body is left in an
unrecognizable state because they are unique to an individual
• Teeth are composed of enamel which is the hardest substance in the body
• The identity of an individual can be determined by comparing a person’s teeth to their
dental records.
• Unusual features including the number and types of teeth and fillings, the spacing of
the teeth, and/or special dental work (bridges, false teeth, root canals) help to make a
positive identification.
• Characteristics of teeth, alignment, and overall structure of the mouth provide method
for identification
• Also analyze bite marks
• X-rays are good record of teeth

19. FACIAL RESTORATION
After determining the sex, age, and race of an individual, facial features can be built
upon a skull to assist in identification.
• The photo imposition technique involves imposing a photo of the skull over a photo
of the face in question.
• Three dimensional reconstruction technique involves adding depth markers for
tissue thickness onto a skull. Erasers are used to make tissue depths at various
points on the skull.
• Clay is placed over the skull, to match the depth of the markers, to simulate skin and
muscle. The features are then smoothed out to make a 'face.'
• This has worked in a number of missing persons cases, but is considered more art
than science.

20. STEPS IN FACIAL RECONSTRUCTION
With a skull:
 Establish age, sex and race
 Plot landmarks for tissue thickness
 Plot origin and insertion points for muscles
 Plot landmarks for facial features
 Select a dataset and mount markers for tissue
thickness
 Mount the eyes
 Model muscles on skull
 Add fatty tissue around eyes and lacrimal glands
 Add eyelids
 Add the nose
 Add the parotid gland
 Add the ears
 Cover all with layers of skin
 Detail the face

21. FORENSIC ENTOMOLOGY
• Study of insects and their relation to
a criminal investigation. Flies, beetles,
and other insects can provide useful
clues about a corpse.
• After decomposition begins, insects
such as blow flies are the first to
infest the body
• Forensic entomologists use factors
such as weather conditions, the
location and condition of the body,
and their knowledge of the life cycles
of insects to help them estimate the
postmortem interval or PMI (the time
between death and the discovery of
the body).

23. FORENSIC PSYCHIATRY
• Specialized area in which the relationship between human behavior and legal
proceedings is examined
– Civil cases: determine whether people are competent to make decisions about
wills, refusing medical treatment, etc.
– Criminal cases: determine whether people are competent to stand trial
– Develop suspect’s behavior profile
• Forensic Psychiatry serves to define what mental illness and disorder are, what
creates mental illness and disorder, how they are diagnosed and how they are treated.
In cases of mental illness, the individual does not function well in reality because of
emotional fluctuations or distorted point of view interpretation.
• Mental disorder is a clinically significant behavior or psychological syndrome or
pattern that is associated with present distress or disability or with a significantly
increased risk of suffering death, pain or disability or important loss of freedom.

24. FORENSIC PROFILING
• Profiling is a label given to the process by which a trained forensic psychologist
sifts through the aspects of a crime scene to develop a description of the
personality of the perpetrator.
• This personality description can include age, sex, occupation, behavioral
disorders, upbringing, marital status, they type of place the perpetuators would
live in and its general condition, the type of person the perpetuators might live
with, what type of car he drives, if he has a speech impediment or acne or some
other type of disability or difficulty in relating to others.
• They will tell you how the crime was committed.
• Profiling does not produce a name. What it does produce is a detailed personality
profile of a perpetrator that investigators can use to focus an investigation and
pare down the list of suspects. It can also provide them with strategies on how to
approach the subject during interrogation and how to break him down on the
witness stand at trial.

25. FORENSIC ENGINEERING
Forensic engineering is the investigation of materials, products, structures or
components that fail or do not operate or function as intended, causing personal
injury or damage to property. The consequences of failure are dealt with by the
law of product liability. The field also deals with retracing processes and
procedures leading to accidents in operation of vehicles or machinery. Generally
the purpose of a Forensic engineering investigation is to locate cause or causes of
failure with a view to improve performance or life of a component, or to assist a
court in determining the facts of an accident. It can also involve investigation
of intellectual property claims, especially patents.
• Concerned with:
– Failure analysis
– Accident reconstruction
– Cause and origin of fires or explosions
• Answer questions such as how did an accident occur or what structural failure
occurred

26. CASES THAT DEAL WITH FORENSIC ENGINEERING
• Fires
– Electrical
– Gas/Propane Explosions
• Accidents
– Mechanical
– Corrosion related
• Electrocution
• Carbon Monoxide Investigations
Root cause failure analysis of
mechanical equipments or parts.
Performing stress analysis, finite
element analysis, fracture mechanics,
corrosion and fatigue analysis on the
failed or deformed components.
Using classical methods or state of art
finite element analysis.

27. FAILURE CLASSIFICATION

28. FAILURE ANALYSIS
Building Materials
• Concrete, mortar and plaster failures.
• Ceramic failures, including cracked, lifting, worn and slippery
tiles, and damaged glass.
• Adhesives and sealants for masonry, tiles and other surface
finishes on buildings and pools.
• Corrosion of pipes and structural steel
• Paint system problems, thickness, peeling and durability.
Motor Vehicles
• Evaluation of substitute components
• Mechanical failure analysis of all components, including
suspension, engine components, transmission and
braking systems
• Tyre failure, including determination of the cause of
blow-outs
• Mechanical failure of components in
the suspension, engine, braking, safety restraint
systems, and tyre failures on passenger and sports
cars, trucks and mining equipment
Engineering Failures
• Structural and component failures in cranes, machines and
aircraft including determination of mechanism and cause
• Non-destructive testing failures
• Assessment of corrosion mechanisms
Public Liability
• Mechanical Failure of products and equipment such
as ladders, chairs, racking systems, motorised
scooters and trolley systems
• Incident investigations involving machines and
equipment, determination of contributing factors,
including compliance with Occupational Health and
Safety and other standards

29. TESTING METHODS
• Accelerated Life Testing – This is a method of testing the life span of a product,
conducted in an environment to stimulate the product’s behaviour in specific
conditions with the results occurring at an accelerated rate.
• Nuclear Magnetic Resonance Spectroscopy – NMR spectroscopy is a technique
that can be employed in the detection of minute traces of impurities in a material.
• Optical Microscopy – Simple microscopy or a hand magnifier may be used for close
examination of the surface of a product. This method can show cracks, scratches,
contamination, and any other defects on the surface of the material.
• Radiography – Using X-rays or neutrons, it is possible to internally examine
products for any defects within the material.
• Scanning Electron Microscopy – A form of microscopy used to detect minute
damages caused to structures or items, it may also be possible to reveal the
presence of harmful or corrosive chemicals on the object.

31. FRACTURE MATCHES
• When an object broken, torn, or cut, two unique edges are formed, which are
referred to as fracture lines.
• These edges can be compared by the naked eye or with microscopes to see if they
fit together , which indicates that they may have been part of the same object at
one time.
• Investigators may compare the edges on pieces of tape, glass fragments, paint
chips, pieces of a car from an accident, paper bag, etc. to find possible matches.

32. FORENSIC PHOTOGRAPHY
Method
Number photo in corresponding photo log book
OVERVIEWS: from farthest part of scene (outward working inward)
MEDIUMS: closer views
UP-CLOSE: close up of items/scene, 2 of every picture, 1 with/1 without scale
Use High Contrast, Zoom, Wide Angle and B/W photographic methods
PHOTOS of Body are taken from all five angles: From above, From feet, From left side, From
right side, and From head

33. FORENSIC PHOTOGRAPHY
• Luminol Photography
• Microscope and Comparative Scope Photography
• Identification Photography
• Fingerprint Photography
• Infrared (IR) Photography
• Ultraviolet (UV) Photography
• Footwear Impression Photography
• Impression Photography
• Electrostatic Dust Print Photography
• Photographing Trajectories
• With Laser Beams

34. SOME EXAMPLES OF UV PHOTOGRAPHY AT CRIME SCENE

35. COMPUTER FORENSICS
• What is Computer Forensics??
– Computer forensics involves the
preservation, identification, extraction, documentation, and
interpretation of computer media for evidentiary and/or root cause
analysis.
– Evidence might be required for a wide range of computer crimes and
misuses
– Multiple methods of
• Discovering data on computer system
• Recovering deleted, encrypted, or damaged file information
• Monitoring live activity
• Detecting violations of corporate policy
– Information collected assists in arrests, prosecution, termination of
employment, and preventing future illegal activity

36. COMPUTER FORENSICS
• What Constitutes Digital Evidence?
– Any information being subject to human intervention or not, that can
be extracted from a computer.
– Must be in human-readable format or capable of being interpreted by
a person with expertise in the subject.
• Computer Forensics Examples
– Recovering thousands of deleted emails
– Performing investigation post employment termination
– Recovering evidence post formatting hard drive
– Performing investigation after multiple users had taken over the
system

37. COMPUTER FORENSICS
Non Business Environment
• Theft of trade secrets
• Fraud
• Extortion
• Industrial espionage
• Position of pornography
• SPAM investigations
• Virus/Trojan distribution
• Homicide investigations
• Intellectual property breaches
• Unauthorized use of personal
information
• Forgery
• Perjury
Business Environment
• Theft of or destruction of intellectual
property
• Unauthorized activity
• Tracking internet browsing habits
• Reconstructing Events
• Inferring intentions
• Selling company bandwidth
• Wrongful dismissal claims
• Sexual harassment
• Software Piracy

38. COMPUTER FORENSICS: STEPS
– Acquisition
• Physically or remotely obtaining possession of the computer, all network
mappings from the system, and external physical storage devices
– Identification
• This step involves identifying what data could be recovered and
electronically retrieving it by running various Computer Forensic tools and
software
suites
– Evaluation
• Evaluating the information/data recovered to
determine if and how it could be used again the
suspect for employment termination or prosecution
in court
– Presentation
• This step involves the presentation of evidence discovered in a manner
which is understood by lawyers, non-technically staff/management, and
suitable as evidence as determined by United States and internal laws

39. WHERE TO LOOK FOR EVIDENCE

40. COMPUTER FORENSICS: STEPS

42. SOIL
• Soil possesses many physical and chemical properties that can be exploited in
comparison of known and unknown samples.
• Soil is produced by a complicated process that is influenced by factors such as
temperature, rainfall, and the chemicals and minerals present in the material from
which it forms. Because of all the factors that affect soil formation, soil from
different locations can have different physical and chemical characteristics that are
useful to forensic scientists.
• The uniqueness of soil composition has helped locate burial sites and link suspects
to crime scenes, identify thief's.
• Soil is part of the top layer of Earth’s crust, where most plants grow. Soil contains
minerals, decaying organisms, water, and air, all in varying amounts. Soil texture
describes the size of the mineral particles that make up soil. There are three main
soil grain sizes: sand, silt, and clay.
• Sand is formed by the action of wind and water on rocks, called weathering. As
wind and water move rocks around, the rocks collide with other rocks. These
collisions break the rock into smaller and smaller pieces until small grains, called
sand, remain.

43. SOIL EXAMINATION
• Layers of soil or mud taken from shoes or the wheels of vehicles can show that a
suspect was present at a series of locations.
• Scientists compare the size, shape, and color of soil by looking at samples
macroscopically for soil type, amount of plant and animal material, and particle
size.
• A systematic approach for forensic soil examination is outlined, which combines
soil morphology (e.g., color, consistency, texture, and structure), mineralogy
(powder X-ray diffraction), chemistry (e.g., based upon infrared spectroscopy
analyses), biology, and spatial field mapping information.
• Soil can also be identified and compared by studies using density
columns, moisture content, and chemical testing for mineral content.
• Before using X-ray diffraction, a soil sample is crushed into a very fine powder. The
powder is then tested, and as the X-ray is deflected, it produces a pattern on a
film. Each mineral and chemical produces a specific pattern. The pattern produced
by the sample allows scientists to determine the mineral composition of the soil.