Forensic Science

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Forensic Science
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Acknowledgement
This powerpoint is based largely on the Chemical
Detective project conducted by Deakin University
between 1999-2005
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Chemical Detective website
The Chemical Detective program is made up of a
forensic science website http//bcs.deakin.edu.au/
bcs_courses/forensic/Chemical20Detective/index.ht
m
a CD ROM of forensic science teaching resources
Aim to encourage the study of molecular and
physical science. It presents science in an
enthusiastic and interesting format with
reference to the real world so as to encourage
Victorian students to continue their science
education into VCE and beyond.
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Chemical Detective website

• For more information contact the Programme
  Coordinator, Dr Simon Lewis at
• School of Biological Chemical SciencesDeakin
  University, GeelongVIC 3217, Australia
• 61 3 52271365       61 3 52271040  
  swlewis_at_deakin.edu.au

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What is Forensic Science?
Crime Solving Identification Evidence
Ballistics Fingerprints
Law Chemical analysis
Anatomy
click here to view definition
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What activities are already being done in class
that can be related to forensic science?
Chromatography
Microscopy
DNA
Invisible Ink
Flame Test
Blood test (theory)
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Example of an aspect of forensic science Blood
Stains Is the sample blood? What is the pattern
of the blood stain?
Fe in haemoglobin catalyses reaction of luminol
to produce blue light. Other things can act as a
catalyst but blood gives a steady glow. Even
after washing or with time, blood still glows.
Hand out
Experiment
Safety!!!
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Chemical Notes

• exothermic reactions
• reaction kinetics (changing conditions)
• effect of temperature

Luminol costs 15 per kit at toy shops.
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Fingerprinting
Types of Prints Dusting Fuming - iodine
crystals
Do experiment
SAFETY!
What Science ??
Crystals subliming Works best with greasy
fingerprints Childs fingerprints have shorter
fatty acid chains and evaporate quicker compared
with adults (iodine attaches to fatty acids and
stains it) Genetics - different patterns of
fingerprints
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Fingerprintingcontd
Compare with other methods of identification of
fingerprints Luminescent fingerprints - use
ninhydrin for staining amino acids (good for old
documents but stains very badly) Superglue
fuming - fluorescent dye (light source, developed
at ANU)
Click here for more info
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Relate to CSF
click here for more info
Physical and Chemical Science Level 6 change of
state spectrum of light atomic structure,
exciting of electrons chemiluminescence - light
sticks Biological Science sweat glands,
inheritance of fingerprints DNA typing
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Careers
End of Chemical Detective
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What is Forensic Science?
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm

• The application of scientific knowledge to solve
  legal problems
• Burglary
• Environmental protection
• International arms control
• Examination and presentation of scientific
  evidence to solve crimes
• Not a new way of science. Applied science.

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When is Forensic Science Needed?
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm

• Police officer arrives at a possible crime scene
• Questions to be answered
• Has a crime been committed?
• Who did it?
• If there is a suspect, can you prove they did it?

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The Forensic Scientist
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm

• The forensic scientist has a three  main duties
• Examination of physical evidence
• Reporting on the results of a forensic
  examination
• investigation in tracing an offender
• presentation of a case to a court
• present verbal evidence in court (expert
  testimony)

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The Crime Scene
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm

• A body has been found, a house has been burgled,
  a car has been broken into
• Forensic science begins at the scene
• recognition of important physical evidence
• preservation of evidence
• No amount of high tech instrumentation or
  expertise will recover a botched crime scene
  investigation

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Physical Evidence
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm

• "any and all objects that can establish that a
  crime has been committed or can provide a link
  between a crime and its victim or a crime and its
  perpetrator
• Saferstein, Criminalistics (6th Edition)
• Chain of custody or continuity of evidence
• Crime scene to the laboratory to the lab report
  to the courtroom.
• If the chain is broken, the forensic
  investigation may be fatally compromised

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Forensic Disciplines
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm

• Forensic science today is increasingly
  multidisciplinary
• pathologists, chemists, toxicologists,
  biologists, entomologists, anthropologists,
  dentists, document examiners, ballistics expert,
  engineers........

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What is DNA?
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm

• Biopolymer responsible for
• passing on genetic information
• Biochemistry of the body
• It is made up of a sequence ofunits based on
  four chemicals
• adenine (A), cytosine (C),guanine (G) and
  thymine (T)

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DNA Structure
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm

• Double strandforms when unitsmatch up to
  formpairs
• G with C
• T with A

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DNA and Individuality
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm

• The DNA of a person is individual and can be
  shown to be theirs beyond reasonable doubt
• How?
• Because DNA has PATTERNS that can be identified
  using modern techniques

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Sir Alec Jeffries
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm

• The first application of DNA typing to forensic
  science
• Dr Alec Jeffries (Leicester University)
• Called in by police to apply his new technique of
  "DNA fingerprinting" to help solve two murders in
  Leicestershire
• Cleared an innocent man

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RFLP DNA Typing
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm
Extraction Extraction of the DNA from the
sample blood, saliva, semen Production of
Restriction Fragments Purified DNA is then cut
into fragments by RESTRICTION ENZYMES
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Patterns in DNA
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm

• Because there are only 4 nucleic acids, patterns
  occur in the DNA
• Take the pattern GCGC
• Imagine it occurs more than once in the DNA
• Number of times it occurs is unique to the
  individual
• Using restriction enzymes we can chop the DNA
  into two at every place where the GCGC pattern
  occurs

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Patterns in DNA
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm
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Gel Electrophoresis
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm
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Visualisation
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm
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Identification
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm

• Parents and children
• Suspects at the scene of crime
• Populations of wildlife species for conservation
  and environmental protection

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DNA Typing Today
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm

• Modern forensic DNA typing based on polymerase
  chain reaction
• DNA polymerases
• enzymes involved in the process of DNA
  replication
• Analysis of minute traces of DNA found at a crime
  scene

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Fingerprints
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm

• Main method of identifying criminals
• Sweat and oils secreted by glands in the dermis
  of the skin
• Tiny ridges of skin on a finger make a pattern
• Each fingerprint is unique
• Even identical twins do nothave the same
  fingerprints

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History
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm

• Ancient History
• ancient Chinese and Babylonian civilisations
• legal documents
• Sir Francis Galton (1892)
• classification of fingerprints.
• Sir Edward Henry (1897)
• modified classification system adopted by
  Scotland Yard in 1901
• FBI (1930)
• National fingerprint file set up in USA

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Fingerprinting Today
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm

• Dusting for prints
• fine powder that adheres to the traces of oil and
  sweat.
• Dusting is unsuitable for porous surfaces like
  paper or cloth another
• Chemical treatments are used
• iodine fuming
• ninhydrin
• superglue fuming

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AFIS
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm

• FBI, Metropolitan Police in London (UK)
• vast collectionsof fingerprints
• making a match
• Automated fingerprint identification systems
  (AFIS)

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Lasers and Fingerprints
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/index.htm
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http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/Luminol_test.htm
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http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/Luminol_test.htm
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Bloodstains
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/Luminol_test.htm

• Bloodstains at the scene of a crime
• occurrence of a blood stain in acertain place,
• shape, position, size or intensityof a
  bloodstain
• blood typing analysis
• Important to be able to
• identify a particular stain as blood or not
• reveal "hidden" bloodstains

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The Luminol Test
http//bcs.deakin.edu.au/bcs_courses/forensic/Chem
ical20Detective/Luminol_test.htm

• Haemoglobin
• red pigment
• transports oxygen around the body
• Luminol Test
• chemiluminescent reaction of the luminol reagent
  with the iron in the haemoglobin

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Career Opportunities

• Forensic Industry
• Insurance claim investigation
• Risk assessment industry
• Government agencies
• Industry
• chemical
• food
• pharmaceutical
• health