CSI – Collecting CSI – Collecting EvidenceEvidence

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Forensics Forensics

ForensicsForensics = the application of = the application of science to law. Forensic science is science to law. Forensic science is used to investigate criminal cases used to investigate criminal cases involving a victim, such as assault, involving a victim, such as assault, robbery, kidnapping, rape, murder robbery, kidnapping, rape, murder and civil cases such as forgeries, and civil cases such as forgeries, fraud, or negligence.fraud, or negligence.

Used in court of law, involved Used in court of law, involved application of science to legal application of science to legal problemsproblems

I.D. of a Firearm & I.D. of a Firearm & Ballistics (travel of Ballistics (travel of bullet until impact) bullet until impact)

When a criminal fires a gun, clues will be left. When a criminal fires a gun, clues will be left. A bullet from a spent cartridge can be traced A bullet from a spent cartridge can be traced to a gun. This is possible because of the basic to a gun. This is possible because of the basic design of a firearmdesign of a firearm

When bullet is fired and travels through barrel When bullet is fired and travels through barrel = rifling cuts mark into the bullet – these = rifling cuts mark into the bullet – these grooved markings are called grooved markings are called STRIATIONSSTRIATIONS and each gun will have different striations and each gun will have different striations which means police can tell what kind of gun which means police can tell what kind of gun was used in a crime if they find a bulletwas used in a crime if they find a bullet

I.D. of a Firearm & I.D. of a Firearm & Ballistics (travel of Ballistics (travel of bullet until impact) bullet until impact)

When they find a weapon, lab technicians When they find a weapon, lab technicians will fire test bullets into a cotton wall or will fire test bullets into a cotton wall or water tank to check power and accuracywater tank to check power and accuracy

Ballistic science can also determine Ballistic science can also determine whether or not a person was holding a gun whether or not a person was holding a gun when it was firedwhen it was fired

Ballistics can also determine the Ballistics can also determine the TRAJECTORIESTRAJECTORIES = path of the bullet = path of the bullet

Forensic EntomologyForensic Entomology

Study of insects to a legal investigationStudy of insects to a legal investigation Insects of interest to because they eat dead Insects of interest to because they eat dead

matter – including humansmatter – including humans Because they have set living and reproductive Because they have set living and reproductive

cycles, insects can be used to establish how long cycles, insects can be used to establish how long a corpse has been dead and if it has been moveda corpse has been dead and if it has been moved

They arrive soon after death and they are cold They arrive soon after death and they are cold blooded so they are attracted to the bodyblooded so they are attracted to the body

Sometimes the movement of suspects, goods Sometimes the movement of suspects, goods and vehicles can also be traced via bugsand vehicles can also be traced via bugs

Forensic ToxicologyForensic Toxicology ToxicologyToxicology is the study of substances which are is the study of substances which are

harmful to human beingsharmful to human beings They have the responsibility of detecting and They have the responsibility of detecting and

identifying the presence of drugs, alcohol and poisons identifying the presence of drugs, alcohol and poisons in fluids, tissues, and organs (i.e., rat poison under the in fluids, tissues, and organs (i.e., rat poison under the sink)sink)

The work of a toxicologist falls into 3 main categoriesThe work of a toxicologist falls into 3 main categories Testing for alcohol in blood or urineTesting for alcohol in blood or urine Identification of drugs such as heroin, cocaine, Identification of drugs such as heroin, cocaine,

cannabis etc.cannabis etc. Detection and I.D. of drugs and poisons in body fluids, Detection and I.D. of drugs and poisons in body fluids,

tissues and organstissues and organs

Forensic ToxicologyForensic Toxicology

Sample types:Sample types: Urine: quick and easy for a live subject, and is common among Urine: quick and easy for a live subject, and is common among

drug testing for employees and athletesdrug testing for employees and athletes Blood: sample of choice for measuring blood alcohol content in Blood: sample of choice for measuring blood alcohol content in

drunk driving casesdrunk driving cases Hair sample: hair is capable of recording medium to long-term Hair sample: hair is capable of recording medium to long-term

or high dosage substance abuse. Chemical in the bloodstream or high dosage substance abuse. Chemical in the bloodstream may be transferred to the growing hair and stored in the folliclemay be transferred to the growing hair and stored in the follicle

Other: samples collected during an autopsy. I.e., stomach Other: samples collected during an autopsy. I.e., stomach contents to detect undigested pills or other common organs contents to detect undigested pills or other common organs such as: eye, brain, liver or spleensuch as: eye, brain, liver or spleen

  

  Handwriting & Ink Handwriting & Ink AnalysisAnalysis

In cases ranging from ransom notes and death threats, to In cases ranging from ransom notes and death threats, to forged cheques and wills, the forensic document examiner forged cheques and wills, the forensic document examiner is called in to examine handwritingis called in to examine handwriting

Want to look at Want to look at NATURAL STANDARDSNATURAL STANDARDS = normal written = normal written material i.e. love letters, cheques, shopping listsmaterial i.e. love letters, cheques, shopping lists

Want to look at Want to look at REQUESTED STANDARDSREQUESTED STANDARDS = request = request person to write them on the spot – problem here is they person to write them on the spot – problem here is they may try to alter writingmay try to alter writing

Also test ink to determine the age of the ink, type of ink, Also test ink to determine the age of the ink, type of ink, whether ink has been removed from a document. I.e. works whether ink has been removed from a document. I.e. works well for historical documents that have been forgedwell for historical documents that have been forged

DNADNA

Last decade DNA has taken huge steps for Last decade DNA has taken huge steps for law enforcement – many feel it’s the law enforcement – many feel it’s the greatest advance in forensic science since greatest advance in forensic science since the intro of fingerprints a century agothe intro of fingerprints a century ago

To use DNA technology some biological To use DNA technology some biological matter must be found i.e. saliva, blood, matter must be found i.e. saliva, blood, semen, vomit, hair + any other fluid – only semen, vomit, hair + any other fluid – only need a sample the size of a pin prick and need a sample the size of a pin prick and can do DNA testing on saliva from a dried can do DNA testing on saliva from a dried cup, a smoked cigarette or a licked stampcup, a smoked cigarette or a licked stamp

Other tracesOther traces

HairsHairs – people lose a minimum of – people lose a minimum of about 100 head hairs every day – about 100 head hairs every day – during a crime they can be shed or during a crime they can be shed or pulled outpulled out

Blood Pattern Analysis Blood Pattern Analysis (BPA)(BPA)

Can look at blood stains at a crime scene Can look at blood stains at a crime scene and determine:and determine:

Type of death i.e. gunshot, stabbingType of death i.e. gunshot, stabbing Where victim was prior and after eventWhere victim was prior and after event Type of weapon usedType of weapon used Amount of force used by offenderAmount of force used by offender How long ago the crime took placeHow long ago the crime took place If offender was right or left handedIf offender was right or left handed WhetherWhether they may be blood on the assailant they may be blood on the assailant

FootprintsFootprints

Shoe marks are the second most common type of evidence Shoe marks are the second most common type of evidence found by the police after DNA, and unique patterns of wear and found by the police after DNA, and unique patterns of wear and scuffing make it possible to match a mark to an individual shoe.scuffing make it possible to match a mark to an individual shoe.

Footwear marks were found at around 40% of crime scenes. It is Footwear marks were found at around 40% of crime scenes. It is even possible to recover a shoe impression from a carpet or a even possible to recover a shoe impression from a carpet or a dead body.dead body.

But although a footmark can show that a criminal had visited a But although a footmark can show that a criminal had visited a burgled house, for example, it would almost always be used burgled house, for example, it would almost always be used with other evidence. It can also give hints towards a person’s 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. height and the manner in which they walk. I.e. limp, walk over.