Forensic Science

Forensic Science

Acknowledgement This powerpoint is based largely on the Chemical Detective project conducted by Deakin University between 1999-2005

Chemical Detective website The Chemical Detective program is made up of: *a forensic science website http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm * 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.

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 52271040swlewis@deakin.edu.au

What is Forensic Science? Crime Solving Identification Evidence Ballistics Fingerprints Law Chemical analysis Anatomy click here to view definition

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)

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!!!

Chemical Notes • exothermic reactions • reaction kinetics (changing conditions) • effect of temperature Luminol costs ~$15 per kit at toy shops.

Fingerprinting Types of Prints * Dusting * Fuming - iodine crystals Do experiment SAFETY! What Science ?? Crystals subliming Works best with greasy fingerprints: Child’s 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

Fingerprinting…contd 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

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

Careers End of Chemical Detective

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm What is Forensic Science? • 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.

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm When is Forensic Science Needed? • 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?

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm The Forensic Scientist • The forensic scientist has a three main duties; • Examination of physical evidence • Reporting on the results of a forensicexamination • investigation in tracing an offender • presentation of a case to a court • present verbal evidence in court(expert testimony)

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm The Crime Scene A body has been found, a house has been burgled, a car has been broken into Forensic science begins at the scene • recognitionof important physical evidence • preservationof evidence No amount of high tech instrumentation or expertise will recover a botched crime scene investigation

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm Physical Evidence "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

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm Forensic Disciplines • Forensic science today is increasingly multidisciplinary • pathologists, chemists, toxicologists, biologists, entomologists, anthropologists, dentists, document examiners, ballistics expert, engineers........

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm What is DNA? • 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)

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm DNA Structure • Double strandforms when unitsmatch up to formpairs; • G with C • T with A

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm DNA and Individuality • 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

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm Sir Alec Jeffries • 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

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm RFLP DNA Typing Extraction Extraction of the DNAfrom the sample; blood, saliva, semen Production of Restriction Fragments Purified DNA is then cut into fragments by RESTRICTION ENZYMES

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm Patterns in DNA • 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

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm Patterns in DNA

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm Gel Electrophoresis 2 1

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm Visualisation

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm Identification • Parents and children • Suspects at the scene of crime • Populations of wildlife species for conservation and environmental protection

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm DNA Typing Today • 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

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm Fingerprints • 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

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm History • 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

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm Fingerprinting Today • 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

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm AFIS • FBI, Metropolitan Police in London (UK) • vast collectionsof fingerprints • making a match • Automated fingerprint identification systems (AFIS)

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/index.htm Lasers and Fingerprints

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/Luminol_test.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/Luminol_test.htm

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/Luminol_test.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/Luminol_test.htm Bloodstains • 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

http://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/Luminol_test.htmhttp://bcs.deakin.edu.au/bcs_courses/forensic/Chemical%20Detective/Luminol_test.htm The Luminol Test • Haemoglobin • red pigment • transports oxygen around the body • Luminol Test • chemiluminescent reaction of the luminol reagent with the iron in the haemoglobin

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

Forensic Science