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Transcript of Forensics
Used in isolated cases.
Types: Most crimes involve some sort of vehicle.
Tire tracks are: Biological (Evidence) Dental imprints Can be used for evidence
Bite marks maybe swabbed for DNA/saliva
Bitemarks are difficult to analyze due to movement of victim/biter's jaw. Fingerprinting 1. Whorls:
34% of the fingerprints are whorls.
Circles,whirlpoolsor spirals that dont exit on either sides.
Plain and central pocket- makes atleast one circle.
Plain: line drawn between a delta.
Accidental: combination of 2 or more types of whorls. Shoe tracks/impressions They are FIRST photographed and then:
Prints are lifted from the surface.
Casted from soft surfaces.
Class evidence (atleast 12 different points must be matched to be conclusive.) Bodily Fluids/ Tissue Evidence Includes: muscle tissue, blood, semen, skin, saliva, tears, mucous and vaginal secretions. Type I-A: clearcut grooves running vertically.
Type I-B: partial length vertical grooves.
Type II: branched grooves (forked).
Type III: intersecting grooves (cross each other)
Type IV: Reticular pattern (wire mesh)
Type V: all other patterns (irregular/other) 2. Loops:
60% of the fingerprints. (majority)
Ridge lines enter from one side and exit from the same.
Radial: opens toward little finger (in reference to right hand).
Ulnar: opens toward thumb (reference to right hand). 3. Arches:
5% of the fingerprints.
Tented when the curvature is less than 90 degrees. Collecting fingerprints:
Iodine fumigation: +ve charged ions (Na+) in sweat react with iodine producing blue black residue.
>light coloured, light-weight fabrics.
Cryanoacrylate (Krazy glue): glue sticks to body oil residue forming white-ish residue-dark coloured surfaces and textured surfaces + glass surfaces.
Ninhydrin spray: reacts with amino acids. (blue purple color)
1 in 64,000,000,000 chance of 2 people having the same fingerprint.
Automated Fingerprint Identification System: AFIS : a computer compares thousands of fingerprints per second using a scoring system. Similar fingerprints are matched by a specialist who makes a final decision. Photographed: to show direction of travel and changes in direction.
Measured to determine tire-track width (the distance between 2 front/back tires) to determine car type.
Cast to show tread (design on tire) indicates particular car type. Chemical (Evidence) Genital/anal, skin and oral tissues swabbed for blood, semen, saliva, tears, mucous and, vaginal secretions.
Fingernail beds- scraped for blood or tissue.
Clothing is obtained and packaged securely for later testing for bodily fluids. Secretors:
Approx. 80% of North American population are "secretors"-contain the same enzymes and proteins in all of their body fluids and tissues.
If a suspect is a secretor, body fluids can be used to help confirm identity.
If they are not a secretor, then other evidence must be found to help prove guilt.
Saliva is tested to determine secretor status. Blood 1. Most obvious and common type of evidence left behind at a violent crime scene.
During violent crimes, if blood vessels are damaged (then the body is in a state of stress) causing an increase in heart rate, making you bleed more.
At the crime scene, it is more important to check for blood as well as materials that may have been used to clean up blood stains. 2. Human blood:
Approx. 5L of blood.
Plasma: straw colored fluid containing water, dissolved nutrients/ions, proteins, minerals and gases.
Red blood cells: Carry oxygen; present in more numbers at higher altitudes (to accommodate for lower oxygen quantity.Life span of 120 days= 4months.
White blood cells: Immune system, destroy pathogens, used for DNA analysis.
Platelets: bits of cells that help for blood clotting. Animal or human blood?
There are numerous tests...some are:
Precipitin test:blood is tested by mixing it in a serum containing animal proteins(antibodies) specific to human proteins(antigens) and looking for clumping(agglutination) (clumping indicates human blood).
Microscopic examination: human RBC's don't have nuclei. 4. Identifying blood: Even if it has been cleaned up, it can be seen easily.
A. Kastle-Meyer(K-M) reagent: phenolpthalein(turns pink with blood)
Detects the byproduct of the breakdown of H2O2by haemoglobin(Hgb)in the cell OH-
Test is fast and sensitive but gives false positives to potatoes and horseradish.
B. Hematest/Hemastic: commercial reagent that reacts with the oxygen resulting from the breakdownof H O to produce a blue colour.
C. Luminol: sensitive reagent for dried or washed-off blood.
Reacts with protein in haemoglobin(heme) causes new and old blood stains to glow with a greenish blue light when it is sprayed on them. Area must be very dark in order to see it.
Limitations: produces a VERY faint glow that is hard to see and photograph.
False positives: metal, bleach and gyp rock.
Causes latent and possibly loody impressions to smear.
Makes diluted stains further unavailable to analyze.
Cumbersome and expensive to use on large areas. (aq) 2 2 Blood typing: blood can be classified(typed) according to the type(s) of protein marker(s)(antigens) that are found on the RBC's surface.
2 types ofblood antigen systems are normally tested to determine blood type: ABO and Rh. These are then put together to give a final result(complete blood type).
(i). ABO system: RBC's may or may not have one or more of the following antigens on their surface.
antigen A: blood type:A (41%)
antigen B: blood type: B (10%)
antigen A and B: blood type: AB (4%)
no antigens: blood type: O (45%)
(ii). Rh system: RBC's either have the Rh antigen on their surface(Rh+) or not(Rh-). Procedure for typing: for both blood systems, types are determined by mixing the RBC's with anti-serum(antibodies) and looking for agglutination(clumping of RBC's).
Type A:clumping with anti-A.
Type B:clumping with anti-B.
Type AB:clumping with anti-A and B.
Type O: no clumping with both anti-A and B.
Type Rh+ : clumping with anti Rh.
Type Rh- :No clumping with anti Rh. Inheritance of blood types: (if you inherit : you will have)
A even from one: AA or AO.
B even from one: BB or BO.
A from one, B from another: AB.
none from any: OO. Punnet squares:
Mother's genes on top.
Father's genes on side. Body fluids other than blood Most sex related crimes(rape/sexual assault, molestation, pedophilia and other indecent acts) are committed by males, so semen is very useful if suspect is a secretor.
During a normal sexual act, a male will ejaculate 3-5 mL of semen.
During the investigation of a sex related crime: victim is taken to a hospital and a physical exam is performed in which a rape-kit is used:
victim's body is searched for injuries and traces of semen, blood, skin, hair.
search areas include: clothes, skin, fingernails, pubic hair, vulva, vagina and anus(males and females).
swabs are taken and tested for traces of semen and for DNA analysis.
victim's clothing/items at the crime scene(i.e. towels used to clean-up) are collectedand tested for traces of semen. Tests for semen:
1. Microscopy: visual analysis under the microscope.
2. "Fast Blue B" test: tests for a protein(acid phosphatase) that is found only in fluids in semen.
When Fast Blue B chemical is combined with acid phosphatase, it turns from blue to deep purple.
False negatives: fungi, some fruits and vegetable juices. Genetics The nucleus of every cell contains chromosomes(46) inherited from your mother and father.
X-chromosome is bigger than Y; 22 pairs look the same in females and 23 in males.
Chromosomes are made up of DNA.and are the genetic blueprints for proteins in your body.
DNA is composed of nucleic acid bases, joined together in 2 strandsthat are wound around each other.
The specific group of base sequences in the DNA strand contain the instructions to make specific types of proteins in the body(gene).
GUANINE-CYTOSINE. 2 Types of DNA(de-oxy ribo nucleic acid): mitochondrial DNA and(normal) DNA.
23 chromosomes inherited only from mother.
single stranded nucleotide sequence codes for proteins made by mitochondria
comparison can be made with maternal family members to: a. identify unrecognizable human remains. b. prove maternity of adopted or missing children. DNA is unique: but only 5% is actually useful, coding for the 30,000 genes your body uses. 99% of that DNA is similar from person to person.
95% is "junk", where one or more base sequences repeat themselves over and over again-VNTR(Variable Number Tandem Repeats).
The numbers, sizes, and positions of VNTR are usually unique to an individual and can be used for "matching" purposes(like: DNA fingerprinting).
A total of 5 VNTR patterns have to be identical to be considered a "match".
Probability ratio predicts the numerical chance that the VNTR pattern could belong to another person. DNA technology: DNA Fingerprinting/DNA print analysis:
allows VNTR patterns in DNA to be identified. 2 methods:
1.) RFLP process: (Restrictive Fragment Length Polymorphism)
DNA extracted and cut into pieces of varying sizes, using restriction enzymes.
DNA is then run on a gel electrophoresisto separate the fragments based on size.
Fragments tagged with a radioactive probe that is exposed onto a piece of X-ray film. Produces individualized band pattern(bar-code).
Advantage: specific probability(1 in 100,000 to 1 in 1,000,000).
Disadvantage: requires about 50,000 cells. 2.) PCR(Polymerase Chain Reaction):
Single strand of DNA replicated quickly, over and over again in a thermal cycler.
DNA run through gel electrophoresis.
Gives result in a fraction of the time of the RFLP method and requires only 50 cells.
Probability of match to prove beyond a reasonable doubt but is lower than RFLP.
As PCR uses smaller DNA fragments, it is less specific.(1 in 1,000 to 1 in 2,000)
Due to smaller size required, inconclusive if sample contains a mixture of DNA(gangrape)(thus results not admissible in court). DOCUMENT ANALYSIS Forensic Document Evidence Analysis Cheques, ransom notes, threatning letters, written confessions and suicide notes are all analyzed to determine the author or if the document has been forged.
Everybody has a unique handwriting style with 3 features to look for:
1. Acquisition of SLOPE: is fixed and can be most seen on lined paper.
2. Size of handwriting: generally the size of letters remains consistent, whether large or small.
FORGED HANDWRITING IS OFTEN LARGER THAN SMALLER.
3. Letter design:
a. Greater variation in letters with tails: q,j,y,g,e,m,s.
b. Less variations in simple letters like o,v,i,c,u,l,t.
c. Capital letters at beginning of sentences are often unique. FORENSICS 30 !!! Alcohol and drugs Toxicology:
A science that studies the origin, nature and properties of various drugs and/or poisons and toxins(including alcohol).
A.) detection and identification of these substances.
B.) detection of these in body fluids, tissues/organs, urine/blood samples. Alcohol:
Alcohol is a natural chemical compound, produced by micro-organisms(yeast and bacteria) during the anaerobic process (in the absence of oxygen) of fermentation.
In humans, 20%of alcohol consumed is absorbed directly into bloodstream, through the stomach. This is why alcohol doesn't take very long to affect your brain.
The other 80%travels through the small intestine, where it is absorbed into the blood-system.
Alcohol in the blood travels to the liver, where it will be broken down by enzymes(Asians don't have that enzyme).
Levels are detected in the blood and urine(technologies: gas chromatography, breathalyzers). Effect of alcohol consumption on your body:
Stomach: irritation of stomach lining, leading to ulcers, bleeding and acid reflux.
Intestines: damages cells, blocking absorption and breakdown of nutrients.
Liver: cirrhosis of the liver(liver hardening), fatty liver and hepatitis(inflammation)
liver becomes non-functional.
Skin: causes dilation of blood vessels, leading to permanent redness of skin.
Muscles: reduction of blood flow to muscles causes weakness and deterioration of the muscle tissue(including heart) (thus they don't feel pain). Forensic Anthropology Study of biological and cultural aspects of mankind in a place at a certain time.
Cultural: customs economic/religious systems(archaeology).
Physical/Biological: physical evolution/development. Analysis an interpretation of human remains to determine the:
Origin of the bones: animal or human.
Number of individuals: mass grave.
Time and cause of death.
Identity of the person(ancestry, gender, age, weight, height, health.) Human 1) Bone cell shape
2) Rib shape/size
4) Upper limbs
Lower limbs Round
- small tubercle projection;
- fewer projections;
- Femur: larger trochanter;
- Angular tibia-unnotched. Animal Rectangular/linear. Linear/straight. Fused - Larger tubercle projection.
- More projections.
- Curved. - Femur: smaller trochanter.
- Flat tibia-notched. Differences between Human and Animal bone: Differences between Male and Female skeletons: 1.) Pelvis 2.) Limbs 3.) Skull Male Female - Tall and narrow;
- larger/more rugged. - Muscle attachment sites:
weight bearing surfaces): large, pronounced where muscles attach. - Super-orbital ridges extreme, (with
Pronounced ridges from facial muscle attachments below the eyes).
- Chin: square and angular.
- Larger teeth. - Short and wide.
- Smaller/slight. - Muscle attachment sites:
weight bearing surfaces): smaller, no ridges, where muscles attach. - Super-orbital ridges slight(gracile) and small,(with- ridges below eye; but slight).
- Pronounced ridges from facial muscle attachments below the eyes).
- Chin: curved and round.
- Smaller teeth. Types of Fractures and Traumas Using bones to determine cause of death:
- Classifications of death:
* often result in skeletal trauma.
(Specific patterns of trauma are often consistent with certain causes of death, but can't be used to prove that they were the " cause of death ". Because, the person could have possibly died before the trauma occurred, the cause of death will be reported as: "being consistent with death by...") Force and types of Bone Fractures: The type of break in a bone depends on the direction from which the force was applied.
Major types of forces causing fractures:
Compression: Force pushes down on bone. Fracture lines often numerous and radiate outward from point of impact.Usually skull and shape of damaged bone matches instrument used to create wound.
Bending: Most common. Force impacts bone at right angle causing triangular break through the cross section of the bone on either the point of impact or on the opposite side. Complete fractures in adults or greenstick in children.
Parry fracture: Results when a person holds up their arms to protect themselves or to ward off a blow in a violent struggle, resulting in inward displacement of the bone.
Shearing: One end of bone is immobilized, while the other is bent. Result of a person attempting to stop themselves from accidentally falling and causes a linear shearing.
Torsion: Twisting forces, usually accidental(skiing, biking) or in child abuse cases. One end of bone is held stationary, while the other is twisted.
Tension: Force pulls on long axis of bone causing dislocation or bone breaks away if strong enough. Displays few fracture lines, and usually occurs accidentally. Types of trauma:
Blow from a wide instrument with a flat or round surface, i.e. clubs, hammers, sticks/rods. Also caused by being pushed or falling onto a hard surface (car accident).
- Affects a wide surface area ; bone compression, bending and shearing.
- Fracture may be comminuted(many bone fragments) with excessive force.
Objects moving through the bone, i.e. bullets, shrapnel.
- Displacement of bone with radiating fracture lines, from the point of impact; injury becomes more diffuse as projectile passes through bone.
- Usually compression force, sometimes bending. Sharp force:
Blow from object having sharp edge/blade i.e. knife, axe, saw.
- Compression/shearing: Force applied towards a narrow focus.
- Puncture: Force applied is perpendicular.
- Grazing cut: Force applied at an angle.
- Complete fracture: "Chopping" type instrument.
- Incomplete fracture: "Cutting" type instrument. Strangulation: Hyoid bone in the larynx is broken in:
8% hanging ; 34% strangulation.
Can not be used to conclude the cause of death under 20 years of age, as the 3 bones may not have fused together (only 7% fused). Entomology: Bugs!? Bugs are used to determine time of death. When a body is "fresh" (within hours of death...), the time of death can be determined by:
Body temperature: (original body temp. is 37 degrees Celsius) Variable based on ambient temperature, humidity, amount of wind, size of body, amount of body fat; body temp decreases about 1.5 C/hr.
Level of lividity: Red discoloration of skin due to blood pooling in lowest areas of body- maximized at 6 hrs after death.
Eyes: Become softer and cloudy film forms within 3 hrs.
Level of rigidity: Rigor mortis starts in eyelids and jaws within 30 mins. to 3 hrs and and spreads within 6-12 hrs. o When the body is days or weeks old, investigators often look for other indicators:
Skin color: Greenish tone starting on stomach 48 hrs after death; marble-like skin 4-7 days after death.
Bloating: Body decays and abdomen bloats by day 10.
Smell: after 31 days; smells like soil.
Skeletonization/Mummification: Formula: y=1285/x (where, x= temp. in C.) o Time Insects present 0-3 Days 4-7 Days 8-18 Days 19-30 Days - Blowflies (bluebottle ; syrphidae)
- Lay eggs within 1-2 days.
- Day 2: larvae hatch- 5mm. - Beetle larvae(Rove)
-Blowflies: day 5- 17 mm. - Ants, beetles.
- Blowflies: pupa- 9 mm. - Beetles and mites.
- Blowflies: adult- between 18-24 days. The kinds and ages/stages of insects found on the body help determine the time of death. Bugs can also tell you whether or not a body has been moved after death:
Some species lay eggs only in sunny or shady conditions and species living in urban areas are different than those in the country. Forensic ballistics The analysis or interpretation of ballistic evidence (bullet holes, damages, trajectories, gunshot holes) to establish the facts in a shooting related crime. 3 categories:
1.) Internal: process occurring inside a firearm when a shot is fired. Examining:
Working mechanisms to determine cause of accidental discharge.
Home-made devices to determine if they are capable of effective discharge.
Examination of fired bullets and cartridge to determine whether or not a firearm was used.
2.) External: study of the projectile's flight from the moment it leaves the barrel until it strikes the target.
Calculation and reconstruction of bullet trajectories.
Determining the maximum range of a given bullet.
3.) Terminal: study of the bullet's effect on the target by determining:
The distance between the firing point and the target.
if a particular wound was caused by a fired bullet.
the caliber and type of projectile that caused damaged or a wound.
ricochet possibilities on targets and fired projectiles. Gun barrels: Evidence that a gun has been fired:
gunpowder residue. Individualized gun barrel marks:
As the bullet passes though the barrel, the lands(raised parts) and the grooves (recessed parts), which are cut into it during rifling to give the bullet spin and increase its accuracy, leave impressions on the fired bullet which are unique to that gun type. Impressions in the rifling process and wear and tear on the barrel leave additional marking that are specific to one particular gun(individualized). Individualized impressions on cartridge cases:
Firing pin impressions and drag marks.
Extractor/ejector marks on auto-loading or repeating firearms- fine striations and gouged impressions on rim and head of the case.
Chamber marks - parallel striation on the cartridge case caused by contact with the walls of chamber. Ammunition terminology:
1.) Cartridge(round) - composed of a case, primer bullet.
2.) Bullet - projectile that contains propellant or gunpowder.
3.) Powder (propellant/gunpowder) - inside bullet casing. Forms as gas which pushes the bullet out of the cartridge and gun barrel. (Old -(black gunpowder)nitrates, charcoal and sulfur; Modern day - (smokeless) nitrocellulose).
4.) Fash hole- small opening that gases go through towards gunpowder.
5.) Primer- volatile chemical compound that detonates the propellant when stuck by the firing pin.
6.) Bullet case/casing - left behind after bullet leaves the gun after firing.
7.) Caliber - the diameter of the bore the bullet(measured end to end in 100th of an inch (0.22cal) or in mm(9mm).
8.) Shell casing - composed of a shot, wad, powder and primer.
9.) Shot - single metal projectile(slug) or many pellets.(birdshot-20-100 small ; buckshot-7-9 large).
10.) Wad - plastic or paper to hold shot together as it is projected. Criminal profiling Investigative technique useful for over 120 years.
Goal: Identify major personality traits and behavioral characteristics of crime committed.
Used to produce list of potential characteristics for crime perpetrator-narrow down suspect list.
Behavioral investigative analysis. Types of criminals used for:
1.Terrorist: Oklahoma city bombing - McVeigh and Nichols.
2.Arsonist: most white males under 21. Unabomber (Kacynski).
Child molesters: most psychosexual(ly) immature (Dahmer, Olson ,Gacy.)
3.Rapist: 75% under 25
4.Serial murders: Mass murders.
- Spree murder.
- Serial murder.
- Visionary (hears voices/visions); missionary (hunt to rid earth); hedonistic (take pleasure in kill). Generating a profile:
Begins by looking at physical evidence of a crime scene.
5 main steps:
1.Gather info from crime scene, victims, witness, autopsy, and forensic evidence.
2.Create sequence of events.
3.Generate list of characteristics of offender: organized/disorganized.
4.Narrow down suspect list.
5.Compare profile with suspect who has been and evaluate report accuracy.
Must be able to explain why characteristics fit offender. Geographical profiling:
Analyze multiple offences believed to be committed by one person.
Used to determine where individual lives (based on the assumption that location of crime is often near the individual's home). Police protective equipment Bullet resistant vests:
Composed of layers Kevlar: 20x stronger than steel.
Bullet gets caught in its network of fibers which absorb and disperse the energy of the impact causing the bullet to deform or “mushroom”.
9mm bullets penetrated layers 5,6,8 and 9(out of 20).
most buckshot did not penetrate. 1.) Kevlar (poly-paraphenylene terephthalamide):
Polymer developed by Stephanie Kwolek at Dupont in 1965.
First commercially available in early 1970's as a replacement for steel in racing tires.
Typically spun into ropes or fabric sheets.
Synthesized in solution from poly aromatic amide monomers 1,4-phenylene-damine(paraphenylene diamine) and terephthaloyl chloride in a condensation reaction.
The resulting polymer must undergo a process called spinning to form a liquid-crystalline structure. During this process, the molten polymer is extruded through small holes, mechanically forcing the polymer molecules to align parallel to each other in bundles which then bond together through H-bonding.
The aromatic components cause the molecules to have a repeating symmetrical radial composition which causes the polymer to be extremely strong.
2.) Taser gun.
3.) Tear gas. Arson What is combustion!?!?
Rapid exothermic redox reaction where a fuel (gases i.e methane; liquid i.e kerosene, gasoline; solids i.e wood) is oxidized in the presence of oxygen producing heat, light, carbon dioxide and water. Incomplete reactions also produce carbon monoxide and solid carbon(soot).
Igniter must be present to initiate the reaction (flame, heat). Fuels: have 3 characteristics:
flash point: the lowest temp at which a liquid produces enough vapour to be ignited by a small flame.
Fire point (self ignition temp): the temp which there is enough heat to cause combustion even in the absence of a source of ignition.
Flammable range: measure of the percentage of fuel that, when mixed with air, is needed to sustain combustion.
Solid fuels: must undergo pyrolysis (the decomposition of solid fuels by heat to form small molecules that can support flaming combustion) in order to properly burn. Investigation of fire scenes: involve classifying fires as either:
Incendiary: (caused by a device/ projectile designed to cause a fire). Steps: to investigate:
1.) Analyze burn patterns: Since heat travels upward, pyrolysis occurs in materials above the area of combustion, producing an “inverted cone-v” burn pattern at the origin of the fire.
2.) Search for causes: Reconstruction/looking for electrical shorts, cooking accidents and careless smoking.
3.) Searching for ignitable liquid residues: Liquids that ignite in the presence of air. Usually not completely consumed and soak downwards near point of origin, while fire burns upward. Sniffers and dogs may be used.
4.) Collect and package debris samples: from point(s) of origin in air-tight containers.
5.) Collection of other physical evidence: empty cans/containers, ignition devices, fingerprints, foot prints, tool marks, blood, ignitable liquid residues. Arson fires:
Burn faster and last longer hotter than normal (often because of accelerant).
Have multiple points of origin.
Often involve accelerants (solid or liquid substances or mixtures that “accelerate” the development of a fire i.e gasoline. When mixed in a proper air-fuel ratio ready to explode).
Often use time-delay devices (for the arsonist(s) to get away).
Often have empty jerry cans nearby (to contain fuel).
Often have unusual odors (usually of accelerant).
Are supplied by a plentiful amount of oxygen. Explosives!!! Caused by a combination of material which alter detonation set off a chemical reaction that produces a gas. The gas increases the pressure within the bomb case, causing the case around the bomb to explode and the pieces to fragment and turn into gas.
Rapidly expanding gases compress the air, creating a physical force(shockwave), which is responsible for the damage. Classified into:
Low: only explode if contained i.e firework and smokeless power (nitrocellulose; and black powder).
Primary high: used as primers/detonators - sensitive to shock, heat and electrical spark i.e nitroglycerin, gunpowder, PETN(penta erythritol) etc. Used as primer in cartridges and in blasting caps.
Secondary high: do not have to be contained to explode; relatively stable and safe to handle; electrical spark, fuel, intense heat or sharp blow initiate reaction, i.e. dynamite, TNT(trinitrotoluene), ammonium nitrate. Plastic (composed of RDX-cyclo trimethylene-trinitramine or a mixture of RDX and PETN), guncotton (soaking cotton in an acid mixture)-used to make plastics. Components of an explosive device: (The explosive train):3 primary components:
1.) Igniter: starts the events(spark).
2)Primer/detonator - contains a primary high explosive(blasting cap).
3)Main charge- determines how explosive; or secondary high explosive(dynamite). Hair The hair root:
1.) Rounded(club) root: Indicates hair fell out naturally.
2.) Follicle attached root: If the follicle is attached to the root (the follicle looks like transparent skin around the root) one can deduce that the hair was forcibly removed, perhaps during a struggle.
3.) Frayed root: this indicates that the hair is likely from a cat.
4.) Spade shaped root: indicates that hair is likely from a dog. The hair shaft:
1.) Imbricate cuticle: Hair is from human. 2.) Coronal cuticle: hair likely came from a dog/rodent (rat, mouse, vole) 3.) Spinous cuticle: hair likely came from a cat. The hair tip:
1.) Slightly rounded tip: individual has not had a haircut in a long time( likely >4 weeks since last cut).
2.) Linear/straight tip: this indicates that the individual has recently had a haircut.
3.) Blackened/frayed tip: individual has come into close contact with flames/ high heat. Variations in the medulla:
1.) Unisereal medulla: hair is likely fom a species of a cat.
2.) Vacuolated medulla: hair is likely from a species of a dog.
3.) Lattice medulla: the hair is likely from a deer/elk.
4.) Multisereal medulla: hair is likely from a rabbit.
5.) Amorphous medulla: hair likely came from a human.
a) continuous amorphous: human with black hair.
b) fragmented amorphous: human with coloured/dyed hair. REFERENCES: Google Images. Wikipedia