Forensics Science Notes PDF

Forensics Science 27/11/12 1:27 PM Chapter 1 1. Actus Reus a. A guilty action 2. Mens Rea a. A guilty mind or intention 3. “Actus non facit reum nisi mens sit rea” a. The act does not make a person guilty unless the mind is also...

Forensics Science 27/11/12 1:27 PM Chapter 1 1. Actus Reus a. A guilty action 2. Mens Rea a. A guilty mind or intention 3. “Actus non facit reum nisi mens sit rea” a. The act does not make a person guilty unless the mind is also guilty 4. Sherlock Holmes is a frictional character by Sir Arthur Conan-Doyle 5. Locard Exchange Principle a. “Every contact leaves a trace” 6. Types of Forensics Science Laboratories a. Physical Science Unit b. Biology Unit c. DNA Lab d. Firearms Unit e. Document Unit f. Photography Unit g. Toxicology h. Latent Fingerprints i. Polygraph i. Lie Detector j. Voiceprint k. Psychiatric profiling l. Computer Forensics and Electronic Forensics m. Forensic Engineering n. Forensic Entomology i. Insects o. Forensic Geology p. Forensic Anthropology i. Examination of skeletal remains q. Facial Reconstruction r. Forensic Odontology i. Teeth 7. Individualization a. Narrowing the class to one i. Physical Object  1. Manufacturer, Serial number, Fingerprint ii. Chemical 1. Trace elements, Impurities iii. Biological samples 1. Blood Type, DNA analysis Chapter 2 1. Robert Boyle a. Elements cannot be created or destroyed 2. Analysis a. Toxicology - Poisoning b. FUN Analysis – Time Of Death 3. Composition a. Bulk composition i. Bullets - Lead b. Trace impurities i. Bullets – Silver and Antimony 4. Spectroscopy a. Excited electron releases a photon of light when it returns back to ground state 5. Flame Test a. Sodium – Orange b. Barium – Green c. Calcium – Red d. Lithium – Red e. Copper – Green f. Potassium – Lilac 6. Atomic Absorption Spectrometer (AAS) a. Advantages i. Fast ii. Specific iii. Sensitive iv. Small sample size b. Disadvantages i. Destructive ii. Element by element 7. Neutron Activation Analysis (NAA) a. Qualitative and quantitative multi-element analysis  b. Requires a Nuclear reactor 8. Scanning Electron Microscopy Electron Dispersive X-Ray Fluorescence (SEM-EDX) a. Using of electrons to eject the core electrons Chapter 3 – Time Of Death 1. Algor Mortis a. After death muscles relax, body limp b. General cooling rule: 1-1.5 F/hour 2. Rigor Mortis a. Lactic acid in muscles causes tension b. Jaw – 2 hrs, Arms (4-6 hrs), Legs (8-10 hrs), Whole body (10-12 hrs) 3. Livor Mortis a. Settling of red blood cells due to gravity b. Discolouration in lower parts c. Ground contact points will be colorless due to contact flattening 4. CO poisoning a. Cherry pink due to carbon monoxide-haemoglobin complex 5. Potassium level in eye a. K+ level in ocular fluid will increase after death 6. Food a. Stomach and Intestine empties after 2 hrs 7. Putrefaction a. 2-3 days: Staining of abdomen, stomach swell due to gas formation b. 3-4 days: Staining spreads, Veins discolored c. 5-6 days: abdomen swells with gas, skin blisters d. 2 weeks: Abdomen very tight and swollen e. 3 weeks: Tissue softens. Organs and cavities bursting. Nails fall off f. 4 weeks: Soft tissues begin to liquefy. Face becoming unrecognizable. 8. Forensic Entomology a. Insects can arrive and lay eggs 20 mins after death b. Collect live maggots from corpse, rear until adulthood then back calculate age and species. 9. Skeletal Remains a. FUN Analysis i. Bone Fluorine and Uranium content will increase from 0% with age 1. Comparable with samples from same site only ii. Bone Nitrogen content in Fresh bone will decrease from 4% by weight b. Fluorescence i. No fluorescence indicates more then 100 years old 10. Carbon-14 Dating a. Measure amount of Carbon-14 and calculate back i. Cannot be used for samples after 1950s 11. Bog Bodies a. Preserves body due to acidity of Bog conditions 12. Otzi a. Body found in the Alps b. Preserved by the cold Chapter 4 – Analysis 1. Thin Layer Chromatography (TLC) a. Presumptive Test b. Advantages i. Cheap and Fast 2. Gas Chromatography (GC) a. The oven is programmable to increase/decrease the oven’s temperature when needed i. First broad peak is usually the solvent ii. Area under peak is proportional to amount b. True for both HPLC and GS i. Efficient, highly selective, widely applicable ii. Only small sample required iii. May be non-destructive of sample iv. Readily adapted to quantitative analysis v. High resolution c. Advantages i. Simple and inexpensive equipment ii. Rapid 3. High Performance Liquid Chromatography (HPLC) a. True for both HPLC and GS i. Efficient, highly selective, widely applicable ii. Only small sample required iii. May be non-destructive of sample iv. Readily adapted to quantitative analysis v. High resolution b. Advantages i. Can accommodate non-volatile and thermally unstable samples 4. Infra-red Spectroscopy a. Stretching frequency depends on masses involved and stiffness of bond b. Fingerprinting region are the ones at the back as there are more details 5. Mass Spectrometry a. Light weight ion deflected strongly b. Heavy weight ion deflected less strongly c. Normally used with GC or HPLC Chapter 5 – Blood 1. Human Blood a. 8% of body weight i. Blood Plasma – 55% ii. Blood cells – 45% 1. Erythrocytes (Red Blood Cells) a. Transports oxygen and carbon dioxide 2. Lymphocytes b. Blood Typing and Antibodies Surface Antigen Blood Antibodies Type A A Antigen Anti-B Antibody Type B B Antigen Anti-A Antibody Type AB A & B Antigen Type O - Anti-A & B Antibody i. You are able to isolate the blood cells from the serum giving blood cells and serum with blood antibodies c. Agglutination  i. Happens when antigen meets with antibody 1. Example A antigen and A antibody d. Rhesus Antigen i. 85% positive, 15% negative 2. Blood Type cannot prove guilt but it can be used to prove innocence 3. Detection a. Benzidine Color Test b. Kastle-Meyer Color Test i. Using of Phenolphthalein and H2O2 ii. Anything that can catalyse oxidation can give a false positive c. Luminol Test i. Luminol with UV light d. Precipitin i. Test using anti-sera produced in pets to bind to human blood 1. Produced by injecting human blood to pets ii. Matching antigen and antibodies form a visible precipitin line 4. Blood Spatter a. Arterial Spurting i. Spray of blood b. Blood Drop i. Exact pattern depends on surface c. Low velocity spatter i. Concentrated with low spatter 1. 1.5 m/s 2. Free fall and cast off d. Medium velocity spatter i. Blood spread across wall 1. 30 m/s – Baseball Bat 2. Medium velocity splatter and cast-off e. High velocity splatter i. Concentrated impact with high amount of spatter 1. Gun shot f. Can be analysis by comparing width and length to find angle of impact i. Able to use to find convergence point Chapter 6 – DNA 1. Chromosomes a. DNA is wound around proteins called histones 2. DNA a. Genes – Coding portion of DNA b. Consist of sugar phosphate backbone with nucleotide i. Adenine ii. Guanine iii. Cytosine iv. Thymine c. Double Helix i. Held in placed by hydrogen bonding d. Genetic code i. Groups of 3 codes for an amino acid 3. DNA fingerprinting a. Uses Junk DNA b. Samples copied using Polymerase Chain Reaction (PCR) c. Min 36 cells (Low copy number – 9) d. Short Tandem Repeats (STRs) i. Pairs – 1 from father, 1 from mother ii. All STR found have to match exactly from both parents iii. Identical twins have identical DNA (May not be true) 4. Chromosomal DNA pairs a. Humans – 23 pairs 5. DNA Testing can be used on non human samples Chapter 7 – Fibres and Polymers 1. Polymer a. Long chain molecules of repeating units 2. Types of Polymers a. Nylon – Adipic Acid & Diaminohexane b. Rubber – Isoprene c. Synthetic Polymers i. Made by extrusion of molten or dissolved polymer 1. Fibre shape and size depends on hole d. Natural Polymers i. Starch – Glucose  ii. Cellulose – Glucose iii. Protein – Amino acids 1. Structural materials – Tissue, Cells, Hair, Nails, Parts of bone 2. Enzymes 3. Antibodies e. Hair i. Anagen Phase: Growth phase, up to 6 years (Contains DNA) ii. Catagen Phase: Transitional phase as growth slows and stops (2-3 weeks) iii. Telogen Phase: Root shriveled and hair can fall out (2-6 months) iv. Cross-section 1. Cuticle – Identification of species 2. Medulla – Width and pattern to identify characteristic of species 3. Cortex – Contains pigment granules (Color, size, distribution, density) v. Chemicals deposited as hair grows 1. 1.25 cm/month f. 3. Analysis a. Which Polymer – IR Spectroscopy b. Color – Dye used identified by TLC c. Shape – Microscope Chapter 8 – Drugs 1. Cannabis a. Extracted from cannabis sativa b. Multiple effects on CNS c. Other names: Marijuana, Pot, Grass 2. Cocaine a. Extracted from leaves of coca plant b. Used for stamina especially at high altitude c. Other names: Crack, Coke 3. Opium a. Extracted from papaver somniferum  b. Morphine is the active component of opium i. Used as a painkiller c. Heroin i. Invented by Bayer Co. ii. More potent than morphine iii. Faster transport to the brain and rapid breakdown to morphine d. Analysis if impurities can show if samples came from the same source 4. Lysergic acid diethylamide (LSD) a. Potent hallucinogen – disrupts communication between neurons b. Popular with the Hippies 5. Amphetamines a. Synthetic compound 6. Ketamine a. Anaesthetic b. Hallucinogen – commonly stolen from Vets and used as date- rape drug 7. Analogs a. “Krokodil” i. Codeine 1. Made from morphine or extracted from opium used in cold medicines ii. Desomorphine 1. Made from morphine but more potent b. “Designer Drugs” i. Analog 8. Detection and Identification a. Marquis Test i. Heroin – Red purple ii. Amphetamines – Orange brown b. Scott Test i. Cocaine c. TLC d. HPLC-MS e. GS-MS f. Immunoassay i. Using antibodies specific for the drug  ii. Color change 9. Penalties in Singapore a. Prison / Fines i. Possession or consumption of cannabis, cocaine, heroin, ecstasy, ketamine b. Death Penalty i. Trafficking 1. Cannabis > 500g 2. Cocaine > 30g 3. Heroin > 15g 4. Methamphetamine > 250g Chapter 9 – Toxicology 1. Systemic Poisons a. Attacks the biochemical systems in the body i. Cyanide – Mitochondria ii. Carbon monoxide – Hemoglobin 1. Formation a. Partial combustion of fuel or organic material 2. Effects a. Prevents blood from transporting oxygen from the lung by binding itself to the hemoglobin complex iii. Strychnine – Nervous System iv. Morphine v. Atropine vi. Pesticides vii. Nerve Agents viii. Arsenic ix. Antimony x. Mercury xi. Thallium 2. Carbon dioxide a. Causes Asphyxiation 3. Toxins a. Natural substances from various species b. Attacks biochemical systems  i. E.g. 1. Box-jellyfish 2. Black Widow Spider 3. Fugu Fish 4. Asp 4. Biological a. Botulism b. Anthrax 5. Definition of poison by Paracelsus a. All substances are poisons; there is none which is not a poison. The right dose differentiates a poison from a remedy. b. Missed out i. A poison must reach its target organ 1. Via absorption into the body 2. Build up in the target organ before excretion 6. Effectiveness of a poison or remedy a. Must be able to reach target organ via either way listed: i. Oral administration – absorbed through digestive tract ii. Intravenous – directly into the blood stream, efficient iii. Inhalation – Rapidly from lungs to blood iv. Through mucus membrane – often fast and efficient v. (GRAPH) 7. Lethality a. LD50 i. Lethal dose at 50% ii. Amount to kill half of a given population of test animals b. Dosage i. Affected by 1. Size – Larger the size, the larger the dosage 2. Age – Metabolism changes with age 3. State of health – especially condition of the liver 4. History – Build up and loss of tolerance 5. Paradoxial reactions – rare but known 8. Xenobiotics a. Xenobiotics are chemicals found in an organism but it is not produced or expected to be present in it i. Maybe any form of pharmaceuticals, illegal drugs, natural substances e.g nicotine, caffeine, etc  b. Accumulation i. E.g. Lead or Strontium in the bones c. Excretion i. E.g. Arsenic or Thallium in hair 9. Alcohol a. Biological effect i. Depresses the central nervous system b. Drink Driving i. Limit 1. >35ug of alcohol per 100 ml of breath 2. >80mg of alcohol per 100 ml of blood o  3. or, even if you are under legal limit, you can still be convicted if you are found to have unsatisfactory control of your vehicle ii. Offenders 1. First time a. Fine between $1000 - $5000, or jailed up to 6 months 2. Second time a. Fine between $3000 - $10000 and jail term of up to 12 months 3. Subsequent convictions a. Fine up to $30000 and maximum jail term of 10 years c. Distribution i. Rate of absorbing depends on kind of drink and stomach contents 1. Absorbed by stomach ~20%, small intestine ~80%  2. Appears in blood in minutes but completes in 30 - 60mins ii. Distributed uniformly via cardio-vascular system which exceptions; 1. Except bones, fats, hair ( Low Water Content ) 2. Higher in arterial bloos then veinous blood due to absorption iii. Detection 1. Measure blood alcohol ( Gas Chromatography ) a. Same concentration as in the brain 2. Measure breath alcohol ( Roadside ) a. Measure loss of absorbance at 420nm iv. Post mortem – Blood, Urine, Vitreous humor v. Henry’s Law 1. For solutions at low concentrations, the vapor pressure of the solute is proportional to its mole fraction 2. Alcohol in blood to alcohol in breath ratio is 2300:1 d. Elimination i. 2 – 5% by kidneys and lungs ii. Ethanol -> Acetaldehyde -> acetic acid -> carbon dioxide e. Blood Alcohol curve i. Back calculate from time of test to time of incident f. Blood Alcohol Calculation g. Inorganic poisons i. Arsenic 1. Detection a. Marsh Test – Ancient Times b. AAS – Now ii. Thallium 1. Lethal Dose – 12mg/kg iii. Sarin 1. Sarin is an acetyl cholinesterase inhibitor, enzyme inhibitor a. Leads to presence of excess neurotransmitter resulting in constant stimulation 2. Facts a. Stockpiled by hitler; never used in WW2 b. Used by Iraqi military against Kurdish villagers c. Used by Aum shinrikyo cult in tokyo subway 1995  iv. Atropine 1. Antidote to Sarin 2. Inhibits action of acetylcholine Chapter 10 – Fingerprinting 1. Fingerprint a. Left by glands excretion of salts, fats, amino acids, proteins and water 2. Comparison with DNA a. DNA i. Can be calculated statistically that no 2 person have the same DNA 1. Other then identical twins ii. Fingerprinting 1. 100 years experience 2. No 2 person have the same fingerprint including identical twins 3. Principles of Fingerprinting a. First Principle of Fingerprinting i. No two person have the same fingerprint including identical twins b. Second Principle of Fingerprinting i. Fingerprint remains for a lifetime even a period of time after death c. Third Principle of Fingerprinting i. All patterns can be classified 4. Lost of Fingerprint a. Capecitabine b. Fingerprint grafting 5. Finding fingerprint a. Visible prints b. Latent prints (Requires chemical detection) i. Dusting Powder (Lift prints with tape) 1. Molybdenum Disulphide 2. Aluminium 3. Carbon Black  ii. Reagents 1. Ninhydrin (reacts with amino acids) 2. Iodine spray 3. Sliver Nitrate iii. Laser fluorescence 1. With dye and without dye iv. Superglue 1. Fume sample in fume hood, add dye and visualize. v. Infra-red Spectroscopy 1. Identification of proteins found in fingerprint Chapter 11 – Firearms 1. Ballistics components a. Internal Ballistics (In barrel) i. b. External Ballistics (During flight) i. Factors affecting the flight 1. Yawing 2. Precession 3. Nutation ii. When a bullet passes through air, the lead bullet softens due to heating 1. Military bullets are coated with a layer of copper to prevent deformation c. Terminal Ballistics (Projectile hits target) i. Bullets can cause injury and death by transferring of its kinetic energy into the target ii. Entry wound is smaller then exit wound 2. Ammunition a. Primers i. Shock sensitive compounds that ignites propellant when struck 1. E.g Lead Styphnate b. Propellant i. Black powder, Nitrocellulose, Nitroglycerine c. Firing Pin  i. Strikes the end of cartridge, primer ignites and propellant explodes 3. Components of a gun a. Bullet i. Bullet Head 1. Target ii. Bullet Case 1. Left at site ( Ejected from Breech) iii. Propellant 1. Gun shot Residue b. Barrel i. Rifling 1. Improves accuracy and stability ii. Striations on Bullet 1. Unique scratch marks on bullet as it travel down the barrel 4. Gun Shot Residue (GSR) a. Deposited near discharged weapon with ~ 1m i. Clothes, surrounding items b. Exception when gun was fired at point blank with mussel flat against the target. GSR will be deposited within wound instead. c. Detection i. Griess Test 1. Tests for presence of Nitrate ( XNO2 ) residues from Nitrate, Nitrocellulose, Nitroglycerine. a. False positive maybe due to fertilizers, urine, cosmetics, tobacco etc ii. Sodium Rhodizonate 1. Tests for lead, barium and antimony from the primer a. Results in color changes i. Sodium – Orange ii. Barium – Red iii. Lead – Black iv. Antimony – Yellow iii. SEM-EDX 1. Identify the elements/compounds present d. However GSR cannot be individualized as there are only 5 types i. Lead, Barium, Antimony  ii. Lead, Barium, Antimony, Aluminum iii. Lead, Barium, Antimony, Tin iv. Lead, Barium, Calcium, Tin; May contain antimony v. Barium, Calcium, Silicon, Tin; May have lead Case Study 27/11/12 1:27 PM Chapter 1 1. Walter Dinivan Body was found with crushed skull, May 21st 1939 Saliva on the cigarette butts found on crime scene indicates blood group AB Joseph Williams was AB o Confesses to crime, story publish after death. 2. Roberto Calvi aka God’s Banker Disappeared on June 11th 1982, found dead on June 19th Things found on scene o Police § Bricks in suit § US$14,000 in wallet § False passport § Bags packed o Pathology § Neck not broken § No drugs § No signs of a struggle § Marks consistent with hanging § No water in his lungs § Watch stopped at 1:52 am 3. Stewart Broughton Severed finger while breaking into a builders’ yard Caught by police while going to hospital for treatment 4. Christopher Paul Neil 2007 5. Buck Ruxton – Jigsaw Murder Murder of “Mrs” Ruxton and maid, Mary Super imposed photos of skull and women’s photo 6. Allied vs Germans Original plan o Use a body of someone who died from a kind of pneumonia that causes the lungs to flood Actual o Vagrant who died from phosphorus poisoning 7. Gordon Hay Killer identified by dental impressions 8. Ronald Benell Dental impressions 9. Wayne Boden Dental impressions 10. Olive Durand – Deacon Body was dissolved in sulfuric acid Identified by false teeth 11. 2005 London Bombings July 7th – 3 bombs on tube, 1 bomb on bus, 52 killed July 21st – 4 bombs failed to explode July 23rd – 5th bomb found abandoned Bombs made using homemade explosive and detonator 12. George Joseph Smith 3 wives drown in bath tub 13. Gareth Williams Padlocked in a sports bag placed in the bath No fingerprint on the bath, Faint DNA traces on the bag 14. Woodchipper Murder Richard and Helle Crafts Richard rented a woodchipper and bought a chain saw Evidence o Chain saw – Human Tissue, Hair, Blue Fibres) o Bleached hair, bone (Type O+), human blood, human tissue, teeth, finger, fingernail and toe nail. Chapter 2 1. Napoleon NAA shows arsenic in hair samples SEM-EDX shows arsenic in wallpaper 2. Kennedy Assassination NAA shows gunman to be one man o Bullet: 20-1200 ppm Sb, 5-15 ppm Ag Chapter 3 1. Peter Thomas  Maggots was found, Jury believes the maggots and not the eye- witnesses 2. Danielle van Dam Fingerprint, blood spot, hair from van Dam family dog in David westerfield’s vehicle Chapter 5 1. Fred Moss a. Killed by Christopher Nudds b. Most blood stains are from birds and rabbits c. Human blood stains found matched Fred Moss 2. Lord Lucan a. Blood found: i. Top of stairs matched Lady Lucan (Type A) ii. Basement match Nanny (Type B) b. Matched Lady Lucan’s story of being attacked in Hallway and nanny at basement making tea Chapter 6 1. Colin Pitchfork a. DNA matched to the murder of Dawn Ashworth and Lynda Mann b. Ian Kelly to submitted blood sample under Colin’s name but was found out 2. Lesley Molseed a. DNA matched to Ronald Castree b. Stefan Kiszko wrongfully imprisoned for 16 years 3. Yorkshire Ripper Hoaxer a. Rapist/Murder, Peter Sutcliffee was caught b. Several letters and tapes sent to the police i. DNA matched John Humble 4. Kirk Bloodsworth a. DNA test shows not guilty b. DNA was matched to Kimberly Shay Ruffner 10 years later 5. James Bain a. Found guilty due to eye witness b. Released due to DNA evidence  i. Jailed for 35 years 6. Lynette White a. DNA was found to be similar to a teenager with a motoring offence b. Eventually matched to Jeffery Gafoor 7. Romanovs 8. Peter Falconio and Joanne Lees a. Blood found on Joanne’s T-shirt b. Low copy DNA found on strap i. Matched Bradley Murdoch Chapter 7 1. Dr Jeffery MacDonald a. Convicted of murdering wife and daughter b. Detected by IR comparison of Synthetic Polymers 2. Robert Curley a. Died via thallium b. Hair analysis shows that he was spiked 9 months before death 3. Wayne Williams a. Analysis found identical yellow-green and violet fibres on clothing of several bodies b. Victims fibres are found in killer’s bedroom carpet, bedspread, dog and car carpets. 4. Sarah Payne a. Fibres found on Sarah’s shoes matched whiting’s red sweatshirt b. Hair found in Whiting’s van matched Sarah’s Chapter 8 – Drugs Chapter 9 – Toxicology 1. Lake Nyos, Cameron a. Landslide causes CO2 in super-saturated lower layer to be released. Resulted in death of over 1700 humans and 3500 livestock. 2. Socrates  a. Coniine 3. Augustus Caesar a. 4. Lakhvinder Cheema a. Pseudaconitine 5. Florence Maybrick a. Murdered her husband with arsenic 6. Maine a. Arsenic found in brewed coffee 7. Graham Young a. Poisons stepmother b. Poisons inmate c. Poisons eight co-worker with thallium or antimony 8. Shizuoka a. Poisons mother with thallium 9. Marie Robards a. Poisons father with barium acetate 10. Georgi Markov a. Jabbed in the leg by an umbrella b. Pellet containing ricin injected into leg by an umbrella Chapter 10 – Fingerprinting 1. Madrid Train Bombing a. Partial fingerprint match to Brandon midfield b. Perfect fingerprint match to Ouhnane Daond Chapter 11 – Firearms 27/11/12 1:27 PM