Assignment 1 Flashcards
What is the role of forensic pathology
concerned with determining death
cause of death e.g. overdose, heart attack, car crash or shooting
manner of death e.g. natural, accidental, suicide or murder
postmortems and autopsies
What is forensic anthropology
study of human remains
used in reconstructions and identification of victims in mass fatalities e.g. war crimes or plane crashes
facial reconstruction e.g. Harjit Singn Luther body found in field disfigured
what is forensic ontology
comparison of dental records before and after death
postmortem dental profiling
comparison of bite mark
what is forensic engineering
investigation of failure analysis of materials and constructions
examine road traffic accidents e.g. paths, speed, direction, driver and type of collision
what is forensic toxicology
chemical analysis of bodily fluids e.g. bloods, urine, tissues for toxic substances
postmortem use to establish if a toxic substance is present
preformed on living to determine level of alcohol in breath or blood
what is forensic psychiatry
behavioral sciences concerned with mental disorders competency to stand trial preparation of psychiatry reports mental state at the time of the offense expert witness treatment
what is forensic psychology
behavioral sciences applied discipline psychological theories of offending offender profiling FBI's behavioral science unit investigative psychology reliability of witness testimony behavior of juries
what is forensic entomology
use of insects and other anthropods as forensic indicators
estimate time of death - postmortem interval
determine whether the body has been moved
determine whether drugs or toxins involved
indicator of abuse or neglect
what is forensic palynology
pollen and spore as evidence
pollen rain and pollen fingerprint
whether a suspect was at crime scene e.g. Ian Huntley
whether a body has been moved from original crime scene e.g. Holly Wells and Jessica Chapman
when is forensic science required
some crimes are obvious but scientific examinations are required
to support an offence of driving under the influence of alcohol and or drugs- blood/ alcohol concentration (80mg/100ml), breath (35mg/100ml) and urine (107mg/100ml)
evidence of drugs such as rohypnol may provide evidence of drug facilitated sexual assault or robbery
finger prints
forensic information database service (FINDS)
finger prints can only be matched if it is in the database - good for catching suspects who have already been processed for a crime
United Kingdoms Central National Database - compares biometric information on those who come into contact with the police.
IDENTI 2010 - 8.3 million finger prints and 8.8 million palm prints
DNA databases
National DNA Database (NDNAD) 2018 - 5.4 million individuals of which 80% are male
around 1% of crimes solved with help of DNA profiling - DNA must already be sampled in the national database
is the suspect responsible
materials characteristic of the suspect left on the victim or at crime scene
blood, semen, saliva, fingerprints, hair and teeth
fibers from clothing, soles of the shoe impressions and material linked to assailants job
tyre prints, oil drips, paint, plastic and glass from vehicles
weapons and tools used
soil, pollen, fingerprint and vegetation
forensic science in the UK
support with police services e.g. scene of crime department, fingerprint bureau, photographic service and chemical enhancement
pre 2012: forensic science service closed march 2012
overtaken by private independent forensic companies e.g. commercial entities and businesses fund them now e.g. Key Forensic Services LTD
concern include outsourcing and Randox scandal - tests results had been manipulated 10500 being reviewed and 2700 being reanalyzed for drug driving
forensic science NI
within the PSNI the scientific support branch provides CSI, fingerprint bureau, photography and mapping and forensic advice
Forensic Service Northern Ireland - budget around £1 million and 20,000 exhibits annually - not including DNA and blood testing
NI DNA database custodian but works with FINDS
key actions in relation to crime scene
preserving evidence e.g. protect from elements such as rain and wind
recording the scene
logging of actions at the scene
searching the scene and gathering evidence
protecting evidence for future processing
assessing the scene
duties of the first officer
carry out initial assessment
deal with emergencies such as bomb disposal, fire service and toxic chemicals
call for assistance if necessary
preserve the scene
make appropriate record of their assessment and actions
communicate this assessment and actions to whoever takes over
provide appropriate info about the processing of the case to those members of the public involved
first officer on the scene may not be in a position to determine whether a crime is in fact been committed
first aid considerations
original position and posture of the person being treated
original direction of flow of any bodily fluids
location, condition and orientation of any objects
presence of any objects in the hands or foreign material under the fingernails
common approach path
accepted practice in the UK
runs from point of police cordon to the focal point of the scene
is chosen in order to avoid contaminating or destroying possible evidence
why record the crime scene
provide permanent record of the crime scene in its untouched state
provide an account of the steps taken during the investigation during the processing of the crime scene
record fragile physical evidence before its recovered in case it is destroyed during the recovery process
resource issues
serious and violent crimes are prioritized
volume crimes such as car theft tent to receive less attention
routine volume crimes can be major in some circumstances e.g. Fiona Pilkington
importance of photographers
damilola taylor
real cases show the importance of photographing objects
if the blood stain on the shoe hadnt have been photographed it would have been harder to establish it later on
commonly collected physical evidence
victims clothing fingernail scrapings head and pubic hairs blood - dna typing vaginal, anal and oral swobs - sex related crime hand swobs, gun shot residue testing recovered bullets from body
preservation of evidence
each different item must be placed in a different container
chain of custody must be established to ensure continuity and integrity
chronological documentation of chain of custody includes record of paper trail, custody, transfer, analysis and disposal
materials/substances that can be used as evidence
blood, semen, saliva hair organs, physiological fluids drugs explosives fibers fingerprints firearms, ammunition glass serial numbers soils and minerals paint petroleum products plastic bags plastic, rubber, other polymers powder residue vehicle lights wood, other vegetative matter impressions tool marks documents
types of evidence
trace- small amounts of material e.g. textile, fibers, glass and paint
biological- blood and other bodily fluids and their stains
toxicological- poison, alcohol or drug presence e.g. some of these may only be taken after death
prints and marks
identification
process of determining a substances physical or chemical identity
chemical composition
nature of explosives
comparison
comparative analysis is undertaken to determine whether or not a subject specimen and a standard/reference specimen have a common origin
both of these are subject to the same test
fibers
2 categories- natural and synthetic
can be transferred to and from crime scenes and from person to person
volume of fibers transferred is related to the frequency and force of contact and the nature of materials concerned
what is used in the laboratory
microscopy
microspectrophotometry (MSP)
thin layer chromatography (TLC)
infrared spectroscopy (IR)
what can hair tell us
colour, length and diameter
size, shape and distribution of pigment granules
damage to hair
presence or absence of nits
when hair was shed e.g. anagen, catagen, telogen
process of analysing glass
speed at which glass refracts light varies
known as refractive index of glass
glass refractive index measurement (GRIM) - fragments are put in silicon oil and heated until the glass disappears which helps to individualise the glass trace evidence
blood patterns analysis
shape, sizes, location and distribution of blood stains can be used in various ways
prove or refute eyewitness accounts
reconstruct a crime
tell us the how of a crime
firearms analysis
type of weapon used
distance between the victim and the weapon
direction of impact
type of ammunition
sequence of shots
whether discharge was accidental or intentional
internal, external and terminal ballistics examination
class to individual
class characteristics - evidence associated only with a group e.g. a red dress from mark and spencer individual characteristics- evidence associated with a common source with an extremely high degree of probability
blood
7.7% of a person’s body weight
55% of blood is plasma
Almost clear liquid- Serum albumin, globulins and enzymes
45% of blood is cells- Red cells erythrocyte, Biochemical markers, White cells leucocyte
Protein DNA = chromatin
blood testing
Presumptive tests: Leucomalachite green (LMG) Phenolphthalein test (KM or Kastle Meyer)
Other tests:
Luminol test- Good for scenes where an attempt has been made to clean up
Precipitin serological test- Human or animal blood
blood types
Development of the ABO system
More typing systems including Rhesus, Kell , Duffy, Lewis, Km and Gm
Discovery of protein variants known as electrophoresis
No. of typing can improve discrimination
saliva
99% water
Produced by three main glands- Parotid, submaxillary and sublingual
Also contains digestive enzyme salivary amylase
Produce 1.5 litres every day
Presumptive test using reagent iodine
role of the forensic medical examiner at crime scene
In cases of suspicious or unexplained deaths, s/he will:
pronounce that life is extinct
make a preliminary examination
record impressions of the condition of the body
inform police of any observations which may help their investigation
preserving evidence
Standard rules apply to all medical examiners.
They must wear protective clothing, make contemporaneous notes and take photographs.
If the FME has to examine both victims and suspects, s/he must be able to demonstrate that no cross contamination could have taken place.
deoxyribonucleic acid
Individual (apart from identical twins, triplets etc.)
Double stranded molecule
Two forms of DNA
nuclear
mitochondrial ( mtDNA)
mtDNA is inherited from the mother: it is less useful forensically
DNA - scientifically
The two long chains of the ladder are sugar and phosphates
The rungs of the ladder are nitrogenous bases: adenine (A), thymine (T), guanine (G) and cytosine (C).
It is the sequence of As, Ts , Gs and Cs running along the DNA molecule that forms the genetic cipher.
identifying an individual from DNA
Dr Alec Jeffreys in 1984 discovered DNA fingerprinting
Initially used in immigration cases
Within DNA there are detectable patterns thus the number of repeats varies between different people and can be used to produce their genetic fingerprint
Chances of getting a DNA profile from
40% saliva
70% semen
>80% blood
DNA breakthrough
First used in a criminal investigation in 1986.
Used DNA fingerprinting techniques to link semen stain samples, collected from two rapes/murders (1983, 1986) in a small village in Leicestershire
Confession for one murder from Richard Buckland exonerated by DNA profile
1987 1st mass DNA screening
1988 Colin Pitchfork convicted of the murders life imprisonment
new techniques
Standard DNA test (SGM+)
C. 50 - 100 cells
Copied 28 times
Analyses 11 areas
Low Copy Number (LCN) test
C. 5 - 10 cells
Copied 34 times
Very sensitive process
concerns of analysing DNA
Working with such tiny fragments means that the reliability may be compromised.
There have also been concerns that the ‘amplified’ samples are more likely to be contaminated: by the person analysing the sample for example.
Justice Weir, acquitting Sean Hoey, accused of the Omagh bombing, was critical of the technique and the safeguards.
caddy review
The use of Low Copy Number (LCN) test was suspended
Reinstated following a review by Professor Brian Caddy, who
concluded that the technique was fundamentally safe
but that it had not been used as effectively as it might have been.
As the techniques used become more complex, can non scientists use them effectively?
