FORENSIC SCIENCE YEAR 2

Minimum skid speed formula
S= √30 Dfn
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S
speed in miles per hour
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30
constant value (gravitational pull)
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D
skid distance in feet
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F
drag factor for the road surface
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N
braking efficiency in decimal form
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What a CSM needs to identify
Look beyond obvious (e.g. body), consider access and egress, identification of suspect and victim route, multiple scenes, everyone who enters scene/in contact with victims/suspects are scenes themselves.
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What a CSM needs to identify
More to think about: where victim was last seen, initial contact site, attack site, body decomposition site, all routes connecting sites, routes to and from scenes that the offender may have used, any vehicles used
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What a CSM needs to Secure
Secure at earliest opportunity, use inner and outer cordon: tape/officers/vehicles/road-blocks/fencing/diversions, inner cordon will include site where victim found and all approach exit paths, outer cordon should include RENDEZVOUS POINT (RVP), PPE
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What a CSM needs to Protect
Prevent movement of exhibits, evidence being obliterated, additional material being added/lost, weather, further human or animal disturbance, consider protection including tents/waterproof covering, others destroying scene and potential evidence
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Continuity
The documented whereabouts of evidence from minute found to minute destroyed
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Integrity
Ensuring evidence is retrieved, handled and stored so that nothing as: Added, Removed, Moved, Destroyed
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Textile fibres: Classification
Manmade (carbon/acetate/cellulose etc), Natural (cotton/wool/silk/mineral), Synthetic polymer fibres (2 materials mixed)
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Textile fibres: Analysis
Microscope: lustre, shape/cross section/size/colour/fibre type
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Textile fibres: Further Analysis/Comparison
Microspectrophotometry, Birefringence (optical property of material having refractive index), dye classification, tape search against control, TLC, FTIR
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Textile fibres: Collection
cover whole surface area, only interested in extraneous fibres, scraping, tapings/handpickings, vacuuming, light source-UV, laser, high intensity
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Evidence: Opinion
evidence of what witness thinks, believes or infers in regard to facts in dispute. Not usually permitted to testify opinions
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Evidence: Expert (Witness)
Someone with specialized education/training/knowledge/expertise/skills/experience relevant to the case *May only be used if scientific/export knowledge understands/determines evidence/fact
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Evidence: Conjecture
An opinion or conclusion formed on the basis of incomplete information. CASE: OJ Simpson -- Defence team, to create reasonable doubt, tried to frame hitman/drug story
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Evidence: Direct vs Circumstantial
Direct: Based on witness's personal knowledge/observation. VERBAL/EYEWITNESS. Circumstantial: makes it seem likely that something happened, e.g. receipt for gun doesn't prove it was used in the crime. PHYSICAL EVIDENCE
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Evidence: Hearsay Evidence
Often termed "secondary" or "second-hand" evidence. Generally considered inadmissible. CASE: Horncastle and Others vs United Kingdom
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Facts in Issue/Material Facts
Facts necessary for a party to prove in order to succeed in the litigation
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Res Judicata
A matter that has been adjudicated by a component court and therefore may not be pursued further by the same parties
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Res Gestae
Meaning "things done"
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KEY CASE: R v Sang [1980] AC 402. (REASON FOR EXCLUDING ADMISSIBLE EVIDENCE)
a judge was able to exclude evidence but not exclude relevant admissible evidence on the terms that it was obtained unfairly, unfairly obtained evidence by undercover police was held as entrapment and they were known as agent provocateur.
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KEY CASE: Expert Opinion... Sally Clark/OJ Simpson
Sally Clark: Professor Sir Roy Meadow testified that the chance of 2 children from an affluent family suffering sudden infant death syndrome was 1 in 73 million. OJ Case: Dennis Fung's "shoo'd dog away" near stains, wore no gloves during collection
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Comparison microscope
Device used to analyze side-by-side specimens. Consists of 2 microscopes connected by an optical bridge, which results in a split view window enabling 2 separate objects to be viewed simultaneously
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Hypostasis (Livor Mortis)
Postmortem lividity. Accumulation of fluid/discoloration of skin due to the pooling of blood in the dependent parts of the body following death
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Pressure area blanching
Area of redness that blanches/turns white when pressure applied, e.g. buttocks
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Petechial Haemorrhage
causes distinctive markings known as petechiae
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Rigor Mortis
affected by temperature, physical activity before death
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Cyanosis
A bluish discoloration of the skin due to poor circulation or inadequate oxygenation of the blood
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Decomposition
State or process of rotting; decay
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Somatic Death
Death of entire body
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Putrefaction
Process of decay/rotting. Skin goes green from CO2, methane, ammonia
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Manners of death
Natural (strokes, heart attacks, etc.), Accidental (falls, RTA, etc.), Suicidal (gunshot, ODs, hangings, etc.), Homicidal: the hand of another
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Prosecutor's fallacy
Assuming that prior probability of a random match is equal to the probability that the defendant is innocent.
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Defence fallacy
Opposite of prosecutor's fallacy... It is to argue that a DNA test is not unique and so even though the defendant's DNA matches, you would expect 10 matches at random against a large database. CASE: OJ Simpson -- defence said blood matched 1 in 400
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Likelihood Ratio
Compares 2 probabilities to find out which most likely... LR = PR (E|S) / Pr (E|U)
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Conditional Probability
P(B|A) = P(A and B) / P(A)
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Actus Reus
Action or conduct which is a constituent element of crime, as opposed to the mental state of the accused, e.g. "failure to prevent death may be the actus reus of manslaughter"
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Mens Rea
whether the individual intended the act or predicted or foresaw the consequences
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FOOTWEAR MARKS: checking photographs...
Photographed to scale, then image printed in reverse. Enhancement: Oblique/UV/IR for photography
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FOOTWEAR MARKS: making impression
Kaffir 'D' Plaster/Crown Stone Impression...Mix dental stone with water in zip-lock bag for 3 mins...stone hardens in 20. 24-48 hours fully hardened
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FOOTWEAR MARKS: pattern and pattern arrangement
Pattern: tread and wear patterns dependent on angle of footfall and weight distribution. Pattern arrangement: class, wear individualisation
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Other cards in this set

Card 2

Front

speed in miles per hour

Back

S

Card 3

Front

constant value (gravitational pull)

Back

Preview of the back of card 3

Card 4

Front

skid distance in feet

Back

Preview of the back of card 4

Card 5

Front

drag factor for the road surface

Back

Preview of the back of card 5
View more cards

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