CRJU211 Summary Lectures PDF

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LECTURE 1: LESLEY WHITTLE CASE: - Lesley Whittle was aged 17 when she was kidnapped from her home in Highly, Shropshire, UK on the 14th of January 1975. - Whittle’s body was found hanging in an underground drainage shaft, Bathpool Park, Kidsgrove, Shropshire, on the 7th March, 1975 - Donald Nielson was arrested on suspicion of Lesley’s murder in Mansfield, Nottinghamshire in July 1976 – a year after the murder NIELSON’S HOME FINDINGS:  Balaclava helmets i. Woollen, purchased from a large clothing retail outlet ii. Had been dyed dark blue – weren’t originally dark blue, but they hadn’t been dyed properly, and with a dye that was not intended for wool, and that was soluble in ammonia iii. Spots of dye were found on the floor in the post office that Neilson had robbed iv. The dye on the floor did not necessarily come from the balaclava helmets v. The dye used was a dylon colour dye for cotton, silk and vicose only – does not stick to wool CHROMATOGRAPHY 1. Put individual fibres into micro-extraction tube 2. Put tube in water, and boil to extract dye 3. Spot extract onto chromatography plate and develop in 2-dimensions DYMO LABEL MAKER: - Single biggest piece of forensic evidence in the case - The angles and distances between the letters of the labels could be have identifying characteristics - The angles and of the labels left at the crime scene were found to be consistent with the label maker machine found in Neilson’s attic – particularly the letter ‘E.’ LECTURE 2: LOCARD’S PRINCIPLE: 1. Locations where crimes take place (crime scenes), contain evidence that links to the perpetrator ‘it is impossible for a criminal to act, especially considering the intensity of a crime, without leaving traces of this presence.’ – Edmond Locard 2. Crime scenes can be processed in a systematic way that allows the discovery of medico-legal and trace evidence. This can be taken away either to a mortuary or to a laboratory for analysis.

HISTORICAL TOXICOLOGY – Mathiew Orfila:  By the early 19th century, one of the most important medico-legal questions was whether someone had been poisoned or not. This was a period where arsenic was very available, and had many house hold uses, and was not regulated up until the 1840s. This period also coincided with the beginnings of life insurance. - French toxicologist Mathiew Orfila proves the necessity of chemical expertise in the 1840 Marie Lafarge case, by coming up with a reliable test for arsenic. Marie Lafarge was accused of poisoning her husband. After he died, Lafarge faced murder charges – initially, the prosecution said there was arsenic in her husband’s body, vomit and food. However, the Marsh test bought in by her defence suggested otherwise THE SPILSBURY ERA: - By the early 20th century, high profile pathologists, like Sir Bernard Spilsbury attracted media and public attention. Spilsbury has sometimes been credited with bringing crime scene investigation to Britain, he in fact continued the body-centred practices that typified forensic medicine - The power and celebrity of men like Spilsbury made it more difficult in Britain for the scene-centered, team-based approach to crime scene investigation to emerge - Reform didn’t take place until 1930s in Britain. THE BIRTH OF THE CRIME SCENE – HANS GROSS: - Austrian investigating judge, Hans Gross, was the first to systematise the methods of crime investigation in his 1893 Handbook for Investigating Magistrates - Gross transformed the crime scene from the realm of common observation to one in which a distinctive set of analytical practices could be applied 1. Preserve absolute calm 2. Exclude everything that happened after the moment of the crime 3. Resist the urge to touch or move anything 4. Treat the crime scene like an open-ended puzzle Gross’ Instructions on How to Construct this Report - He suggested primitive drawings to register the spatial and relational details of a scene - This might be improved further by using objective reference points worked out with a compass, spirit level or plumb-line angles - Once recorded in the report and carefully collected, the traces of the crime could be taken to the crime laboratory to reveal their secrets LECTURE 3 PRINCIPLES OF FORENSIC SCIENCE: 1. LOCARD’S EXCHANGE PRINICIPLE – TRANSFER OF EVIDENCE  The perpetrator of a crime will bring something into the crime scene and take something away from it.

COCCOLITHS:  Small creatures that sedimented to form chalk. There are many different, distinct types of coccoliths. Norman West discovered the value of them in the 1970s. - Originally, putty which was made from chalk and oil was used to glaze windows. In the putty, are a span of coccoliths characteristics of that specific putty. - As a perpetrator of a crime, i.e burgling, you may end up with a fragment of putty on your clothing, which can be tracked by smearing it under a microscope and identifying the coccoliths and their ratio – this can then be matched to the window - Coccoliths are collected from clothing in a laboratory using a magnifying glass and lifting tape, and characteristic features of the clothing’s fibres are recorded meticulously Refractive Index – Measurement of Glass Identification: a) measure of how fast light travels through a material compared to speed of light in a vacuum – i.e the refractive index of water is 1.33. b) Refractive index of microscopic glass fragments can be measured c) Compare fragment RI from accused with control d) Not definitive evidence e) Adds to the forensic picture of the case LECTURE 4 – CRIME SCENE INVESTIGATION: PREVENTING CROSS CONTAMINATION: 1. Non-static, non-fibre attracting overalls 2. Head covered – prevent DNA transfer, hair 3. Gloves – touching evidence as little as possible PROCESS OF CRIME SCENE INVESTIGATION: 1. Scene survey and evidence recognition – eg. documentation, weapons 2. Scene searches – very methodical, depends on the scene type – can be reviewed through a spiral, line, or grid search method 3. Documentation – Accurate/detailed notes of the scene, dated and signed in order to be used as admissible evidence in court. Often contains dated and signed diagrams and sketches accurately labelled, and photographs. These should be used as tools to enable the reconstruction of a crime scene 4. Evidence collection and preservation – prevent contamination, label accurately, make sure the person who collected the samples is clear on the label, seal the sample to prevent contamination or tampering (often heat sealed), and use a label system to record the passage of the sample from person to person (i.e from scene to lab)

5. Release of scene – only when notes and photographs have been taken and diagrams have been made – is a point of no return, you cannot go back after the crime scene has been released due to risk of contamination LECTURE 5: FORENSIC CHEMISTRY TECHNIQUES: CHROMATOGRAPHY: 1. Thin Layer Chromatography (TLC)  Used to identify dyes from fibres a. Spot extract the dye onto an aluminium or glass plate b. Put the plate in a developing tank c. Analyse pattern - TLC separates molecules in order of their solubility - Results are more valid with a consistent separation in the middle between fat and water soluble molecules - The bigger the plate number, the higher level of separation molecules and therefore reliability 2. High Performance Liquid Chromatography (HPLC)  Used to identify drugs of abuse - Similar science to TLC – the solvent runs from the top, through the plate, and comes out the end molecularly separated - Used to distinguish between different illicit drugs, eg. amphetamines and methamphetamine – separates the molecules out, with the molecular difference suggesting the drug in question - The area to the height of the peak is proportionate to the concentration - These techniques can separate very similar molecules – incredibly sophisticated technology 3. Gas Liquid Chromatography (GLC)  Used to identify fire accelerants, blood alcohol analysis - Flame changes colour or ionisation to indicate molecular separation - Commonly used for blood alcohol analysis – alcohol usage can be measured, and the alcohol itself can be identified - Can be used in an arson case – to test the accelerant suspected of starting the fire. Rag is placed in a glass vessel and analysed through GLC-MS analysis which shows all of the molecular structure of a specific accelerant. This diagnostic can then be compared with the disputed accelerant sample 4. Mass Spectrometry (MS)

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Bombard molecule with ions or electrons in a vacuum  molecule fragments are charged, and can be separated according to their specific weight and charge coupled with HPLC and GLC for definitive identification - Absolute in court Accurate mass increases the reliability of the analysis MS is used as a very specific detection/identification method for HPLC and GLC

EXTRACTION OF DRUGS FOR ANALYSIS: 1. Liver sample/stomach contents 2. Homogenise/blend 3. Solvent extract Concentrate 4. HPLC analysis LECTURE 6 – FORENSIC BIOLOGY: DIATOMS: - Silica cell walls - Robust – will last for a very long time - Mainly, but not entirely aquatic – eg. may be found in a body that has been drowned or been left in a body of water - Can be identified microscopically, and by DNA Scenario:  Partly decomposed body floating in the river – did the person drown, or was a murdered body dumped in the river? - Live body drowning inhales water – diatoms. Therefore, diatoms in the lungs suggest drowning, and specific species of diatoms can identify the drowning site. - Dead body dumped into the water – usually no water inhalation in the lungs - Ratio of the different species should also be considered as part of the evidence TISSUE IDENTIFICATION: - Section thinly – 5 microns, and stained with a particular dye, to stain the nuclei dark and the cytoplasms red - Brain tissue is wholly different from tissue from another area of the body eg. liver. This, in combination with species, would be able to help distinguish what was on the person LECTURE 7 – FORENSIC BIOLOGY: Insects on Cadavers – Determining the time of Death: - Blowfly lays eggs soon after the death - Life cycle intervals at particular temperatures of flies are well known

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Determining which life cycle stage is present on the corpse indicates the time since the death SUMMARY:  Biological techniques used in forensic science are very broad, they include; a. Diatoms in drowning cases b. Pollen and plant debris to link a person with a place c. Blood grouping of blood stains d. Identifying tissue from clothing e. Using acid phosphatase to locate semen stains on clothing f. Using insect life-cycles to estimate time since death LECTURE 8: DNA IN CRIMINAL DETECTION DNA:  DNA – or Deoxyribose Nucleic Acid is a set of blueprints for cells, which instruct each cell on their particular job. However, these blueprints are written in a code, made up of four letters called bases. These bases bond together specifically – A bonds with T and C bonds with G, to form a three-letter sequence known as a codon. When codons join together, they form a protein, which then folds into the DNA structure – the easily recognisable double helix shape. The sequence of DNA is incredibly unique to each individual, meaning no two people can have the same DNA.  DNA can be analysed from a variety of samples in criminal cases, as it is found in hair follicles, fingerprints, semen, saliva and white blood cells. Samples taken can be very small, as just one picogram of DNA is required to undergo testing. Once the DNA has been analysed by forensic scientists, it can then be submitted to a DNA library to ‘find’ a suspect. A DNA library is a database to which forensic scientists and police have access, which contains the DNA of those accused and convicted of previous crimes. A forensic scientist can enter the results of a DNA sequence into this library and it will produce any ‘matches’ to the DNA that may already be in the system. Using DNA in Forensic Cases: - Isolate DNA – miniscule amounts (nanograms) - Amplify specific bits of DNA – using Gel Electrophoresis and Polymerase Chain Reaction, which multiplies the chains of DNA so they become more identifiable - Analyse DNA fragments – patterns, sequences, unique to each human - Compare DNA pattern from suspect/accused and DNA recovered from victim or vice versa - Use DNA library to ‘find’ a suspect GEL ELECTROPHORESIS: - Chromatography, a positive charge is place and one end and a negative charge at the other.

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Isolated DNA is put on the plate, and the machine is turned on and left on for the process to occur DNA is separated on the basis of size and charge, producing a pattern of individual pieces of DNA

LECTURE 9 DNA CONTINUED: SUMMARY: - Basic structure and function of DNA is the genetic material, involved in inheritance, - DNA is in cell nucleus and mitochondria – red blood cells do not have DNA as they don’t have either of these - DNA sequence is person-specific - DNA can be stable for thousands of years – eg. the Egyptian Mummies - There are 2 types of DNA – coding (Exon) and non-coding DNA (Intron) - Non-coding DNA has many mutations, depending on the environment the person lives in, external factors - Non-coding DNA has the Short Tandem Repeats (STRs), used in forensic casework - Very, very, very unlikely that two people have the same STRs, even twins  In casework: DNA is isolated, eg. from a bloodstain, the Short Tandem Repeats are then amplified by Polymerase Chain Reaction, separated by Gel Electrophoresis, and the patterns are compared and analysed with accused. LECTURE 10: FINGERPRINTS: HOW TO EXTRACT LATENT FINGERPRINTS FOR ANALYSIS: 1. Ninhydrin Test for Amino Acids: - Spray a latent fingerprint with ninhydrin acid solution and it will turn purple where the amino acids are, representing the surface of the skin 2. Iodine Fuming: - Iodine is soluble in fats - It forms a gas easily – this gas is purple - Latent fingerprints put into the atmosphere of an iodine gas, and then they form a yellow/brown colour 3. Dusting: - Uniform very small particle size powder - Aluminium powder commonly used - Dusted with brush across latent fingerprint - Powder sticks to fingerprint Analysing Fingerprints:

 Put values into the equation by analysing characteristic features, eg. whorls, loops, arches etc – to produce a numerical value, which can be compared. Fingerprint recognition and comparisons can be done digitally – bioinformatics. LECTURE 11: TOXICOLOGY: PROCESS:  Forensic toxicologists perform scientific tests on bodily fluids and tissue samples to identify any drugs or chemicals present in the body. Working in a lab, the forensic toxicologist performs tests on samples collected by forensic pathologists during an autopsy or by crime scene investigators. 1. Circumstances of the case are considered 2. Post-mortem – organs are removed, weighed, photographs are taken etc. 3. Samples are taken, eg. tissues and body fluids eg. blood, urine, bile 4. Extraction chemical analysis 5. Identify Quantity – the amount of toxic chemical present 6. Toxic chemical present? Fatal dose? Dealing with the Samples: 1. Remove a section from the post mortem liver sample 2. Homogenise the sample in a blender 3. Put the sample in a funnel along with a solvent extract, shake the funnel – repeat this process each time of shaking the solvent and homogenise, and collect the residue which will contain the chemicals that were in the liver 4. Take solvent extract, evaporate it down, and put solvent back into it to dissolve the residue 5. Concentrated extract can then be analysed via HPLC with mass spectrometry LECTURE 12: TOXICOLOGY CONTINUED: Analysis of Radioisotopes: Radioactive Decay: 1. Alpha: Heavy, high energy particles from nucleus, positive charge, not very penetrating (stopped by paper) – by far the most toxic. Particles from different isotopes have different energies. The amount of energy from an alpha particle is so big that it can be measured in tiny amounts. 2. Beta: Small, electrons, negative charge, reasonably penetrating (stopped by thin glass) 3. Gamma: Electromagnetic waves, very penetrating (stopped by thick lead eg. 1-2m, concrete, 10-15m) LECTURE 13: DRUGS OF ABUSE:

ANALYTICAL PROCESS: - Powder/Crystals: directly to HPLC testing - Weed, Residues, Blood and Urine Samples: solvent extraction before going through HPLC testing – tetrahydrocannabinol (THC) must be found in marijuana - Manufacturing impurities might be important to help identify the maker TERM 2: LECTURE 14: FORENSIC PATHOLOGY Post-Mortem Examination (Autopsy) PROCESS: 1. External Examination - Signs of injury, wounds, bruising, fibre/tissues under fingernails – skin under fingernails, soil, plant debris etc. Pathologist use a nail file with a hook to obtain this evidence - Photographs are important, because once the post-mortem has started, evidence will likely be damaged - Voice recorder – often used to explain damage, giving indication of where it is, number the damage, photographed so the damage can be cross-referred to Teeth and Dental Records: - Important in identification - Post-mortem X-ray is performed as part of the external examination - Dental records are very unique – used particularly for identification purposes 2. Internal Examination - Very strategically conducted – the exact same cuts are always made - Signs of internal damage - Signs of disease - Looking at organs – organs are put back in again afterwards unless they have evidential value 3. Microscopical - Signs of damage - Signs of disease - Histopathology – process of examining organs using stain and microscope, involves slicing the organs 4. Biochemical/Analytical - Signs of disease - Blood biochemistry - Evidence of unexpected chemical contamination eg. drugs LECTURE 15: FORENSIC PATHOLOGY CONTINUED: EXTERNAL POSTMORTEM WOUND EXAMINATION: - Stab wound: You are able to get a lot of information about the knife and trajectory etc. of a stabbing victim by analysing the stab wounds. A better picture of what the weapon might be assists the police with tracing back to the offender.

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Blunt trauma wound: the extent of the force of the wound can only be seen by looking inside of the victim. Dark bruising occurs when someone is alive, and the yellowish bruises tend to occur when someone is dead – but not always. Skin: cells can be distinguished to work out whether the skin is healthy or not through a microscope. Skin shows up very differently through a microscope. Bodily fluids: Samples are taken eg. urine, bile, stomach contents Gastric Wischnewksy Spots: denote hypothermia and are characteristic of people who have died of hypothermia. As a result of severe trauma, victims can suffer from hypothermia as their body temperature regulators become upset.

LECTURE 16: FIRERARMS Distinguishing Characteristics of Guns, Cartridges and Bullets: 1. Rifling: Grooves cut in the barrel in a spiral like fashion of a rifle to give the bullet spin – the faster the spin, the greater the speed of the bullet 2. Lands: Metal peaks between rifling grooves 3. Grooves: Valleys between lands 4. Calibre: Diameter of the gun barrel in inches (45 calibre gun = 0.45 inches diameter) – bigger the caliber, bigger the barrel of the Gun Firing a Gun: 1. Bullet flies out, cartridge flies in the other direction 2. The metals bullets are made from are reasonably soft, and therefore are modified by the firing process. During the firing process, the grooves on the inside of the rifle will scratch the surface of the bullet, and the lands have also made an impression on the bullet. These impressions will suggest the direction of the bullet’s flight. 3. A particular type of gun will always have the same angle of rifling impressions. Investigate the Firearm: - Check the firearm barrel for any defects of any kind which may be distinguishing - Damage can suggest it is an older gun – as older guns more often have unique combinations of damage - Identify aberrations, twists, etc. - Investigate the cartridges – test-fire in suspect gun, compare patterns with recovered cartridge - Comparison microscopy – brings the images together Chemicals In Gunshot Residues:  Analytical method: Scanning Electron Microscopy/Energy Disp...