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CSI – Collecting Evidence Forensics Forensics = the application of science to law. Forensic science is used to investigate criminal cases involving a victim, such as assault, robbery, kidnapping, rape, murder and civil cases such as forgeries, fraud, or negligence. Used in court of law, involved application of science to legal problems I.D. of a Firearm & Ballistics (travel of bullet until impact) When a criminal fires a gun, clues will be left. A bullet from a spent cartridge can be traced to a gun. This is possible because of the basic design of a firearm When bullet is fired and travels through barrel = rifling cuts mark into the bullet – these grooved markings are called STRIATIONS and each gun will have different striations which means police can tell what kind of gun was used in a crime if they find a bullet I.D. of a Firearm & Ballistics (travel of bullet until impact) When they find a weapon, lab technicians will fire test bullets into a cotton wall or water tank to check power and accuracy Ballistic science can also determine whether or not a person was holding a gun when it was fired Ballistics can also determine the TRAJECTORIES = path of the bullet Forensic Entomology Study of insects to a legal investigation Insects of interest to because they eat dead matter – including humans Because they have set living and reproductive cycles, insects can be used to establish how long a corpse has been dead and if it has been moved They arrive soon after death and they are cold blooded so they are attracted to the body Sometimes the movement of suspects, goods and vehicles can also be traced via bugs Forensic Toxicology Toxicology is the study of substances which are harmful to human beings They have the responsibility of detecting and identifying the presence of drugs, alcohol and poisons in fluids, tissues, and organs (i.e., rat poison under the sink) The work of a toxicologist falls into 3 main categories Testing for alcohol in blood or urine Identification of drugs such as heroin, cocaine, cannabis etc. Detection and I.D. of drugs and poisons in body fluids, tissues and organs Forensic Toxicology Sample types: Urine: quick and easy for a live subject, and is common among drug testing for employees and athletes Blood: sample of choice for measuring blood alcohol content in drunk driving cases Hair sample: hair is capable of recording medium to long-term or high dosage substance abuse. Chemical in the bloodstream may be transferred to the growing hair and stored in the follicle Other: samples collected during an autopsy. I.e., stomach contents to detect undigested pills or other common organs such as: eye, brain, liver or spleen Handwriting & Ink Analysis In cases ranging from ransom notes and death threats, to forged cheques and wills, the forensic document examiner is called in to examine handwriting Want to look at NATURAL STANDARDS = normal written material i.e. love letters, cheques, shopping lists Want to look at REQUESTED STANDARDS = request person to write them on the spot – problem here is they may try to alter writing Also test ink to determine the age of the ink, type of ink, whether ink has been removed from a document. I.e. works well for historical documents that have been forged DNA Last decade DNA has taken huge steps for law enforcement – many feel it’s the greatest advance in forensic science since the intro of fingerprints a century ago To use DNA technology some biological matter must be found i.e. saliva, blood, semen, vomit, hair + any other fluid – only need a sample the size of a pin prick and can do DNA testing on saliva from a dried cup, a smoked cigareete or a licked stamp Other traces Hairs – people lose a minimum of about 100 head hairs every day – during a crime they can be shed or pulled out Blood Pattern Analysis (BPA) Can look at blood stains at a crime scene and determine: Type of death i.e. gunshot, stabbing Where victim was prior and after event Type of weapon used Amount of force used by offender How long ago the crime took place If offender was right or left handed Whether they may be blood on the assailant Footprints Shoe marks are the second most common type of evidence found by the police after DNA, and unique patterns of wear and scuffing make it possible to match a mark to an individual shoe. Footwear marks were found at around 40% of crime scenes. It is even possible to recover a shoe impression from a carpet or a dead body. But although a footmark can show that a criminal had visited a burgled house, for example, it would almost always be used with other evidence. It can also give hints towards a person’s height and the manner in which they walk. I.e. limp, walk over.