• Save
Elements Of Forensic Science
Upcoming SlideShare
Loading in...5
×
 

Elements Of Forensic Science

on

  • 4,814 views

 

Statistics

Views

Total Views
4,814
Views on SlideShare
4,807
Embed Views
7

Actions

Likes
8
Downloads
0
Comments
1

1 Embed 7

http://www.slideshare.net 7

Accessibility

Categories

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

Elements Of Forensic Science Elements Of Forensic Science Presentation Transcript

  • Elements of Forensic Science Types of Evidence Related Services
  • Elements of Forensic Science
    • Firearms and Toolmark Identification
    • Forensic Psychiatry and Profiling
    • Questioned Document Examination
    • Criminal Law
    • Careers in Law Enforcement
    • Forensic Photography
    • Personal Identification
    • Crime Scene Processing
  • Firearms and Toolmark ID
    • ballistics and bullet matching
      • each firearm has it’s own “signature” in the rifling in the barrel
        • lands and grooves spiral down the barrel
        • soft lead is forced into these areas creating microscopic scratches thus marking the bullet
  • Firearms and Toolmark ID
    • ballistics and bullet matching
      • these scratches are unique to one particular firearm
      • tested in lab by firing a bullet through the suspect weapon
        • test fired bullet compared to crime scene bullet
        • if striations(scratches) line up – a positive match is made
        • if striations don’t line up, result is negative
  • Firearms and Toolmark ID
    • ballistics and bullet matching
      • much debate about “ballistic fingerprinting”
        • barrels can be changed out completely or filed down
        • barrels and firing pins also wear with time changing the “fingerprint”
        • firing pins can be easily modified
  • Firearms and Toolmark ID
    • imprint evidence
      • two types
        • three dimensional ex. car tire in mud
        • two dimensional ex stepping in paint
          • this type leaves two imprints – one in the paint (a negative image) and one from the bottom of the shoe onto a new surface (like a rubber stamp)
        • can be so detailed it can be used to identify class and individual characteristics
  • Firearms and Toolmark ID
    • imprint evidence
      • tire impressions
        • tread evidence
        • pattern of long tire impression can yield additional information
          • wheel base distance
          • direction car facing
          • how they pulled out
          • direction of travel
  • Firearms and Toolmark ID
    • toolmark identification
      • three types of toolmark impressions
        • compression – a tool surface presses into a softer material
        • sliding – a tool scrapes across a surface causing parallel striations
        • cutting – a combination of the two
      • all three types can yield class and individual characteristics
  • Firearms and Toolmark ID
    • explosives
      • residue can be analyzed to determine type of explosive
        • some manufacturers are putting chemical tags in their explosives that allow for tracking of specific batches
      • detonator can be analyzed for origin of component parts
  • Forensic Psychiatry& Profiling
    • forensic psychiatry
      • serves to define
        • what mental illness and disorder are
        • what creates mental illness and disorder
        • how they are diagnosed
        • how they are treated
  • Forensic Psychiatry& Profiling
    • forensic psychiatry
      • mental illness – the individual does not function well because of emotional fluctuations or distorted point of view interpretation
      • mental disorder – clinically significant behavior or psychological syndrome or pattern that is associated with present distress or disability or with a significantly increased risk of suffering death, pain or disability or loss of freedom
  • Forensic Psychiatry& Profiling
    • forensic psychiatry
      • issue of incompetency is fitness to stand trial
        • must understand what is going on
        • can help in their own defense
        • three bases of incompetency
          • emotional/psychological factors
          • cognitive or intellectual factors
          • physical factors
        • competency evaluation must be done – cannot be refused
  • Forensic Psychiatry& Profiling
    • forensic psychiatry
      • issue of insanity applies to mental state of defendant at time at which the crime was committed
        • defendant must concede guilt at time of insanity plea
        • defendant must be competent to stand trial
        • defendant must prove profound defect of mental ability – this must be directly related to the crime
  • Forensic Psychiatry& Profiling
    • profiling
      • process by which trained forensic psychologist sifts through aspects of the crime to develop a description of the personality of the perpetrator
      • “ Behavior reflects personality.” (John Douglas, Mindhunter )
      • process works because of extensive database
        • interviews of hundreds of convicted serial killers, serial rapists, and mass murderers
  • Forensic Psychiatry& Profiling
    • profiling
      • description can include
        • age
        • sex
        • occupation
        • behavioral disorders
        • upbringing
        • marital status
        • type of living quarters and general condition
        • type of person the perpetrator lives with
        • what type of car is driven
        • any disability or difficulty in relating to others
        • how the crime was committed
  • Forensic Psychiatry& Profiling
    • profiling
      • description can be used to
        • focus investigation on particular suspects
        • provide strategies on how to approach suspect during interrogation
        • provide strategies on how to break him down on the witness stand at the trial
      • Criminal Minds
  • Questioned Document Analysis
    • handwriting analysis
      • examination of design, shape and structure
      • determine authorship
      • basic principle is that no two people will write the exact same thing in the exact same way
  • Questioned Document Analysis
    • handwriting analysis
      • characteristics
        • letter formations
        • connectors
        • upstrokes
        • retraces
        • down strokes
        • spacing
        • baseline
        • curves
        • size
        • distortions
        • hesitations
        • flying stops
  • Questioned Document Analysis
    • typewriting
      • much like firearms, typewriters of the same make and model are pretty much the same
      • daily wear and tear or parts of the machining process can cause “defects” or individual characteristics that translate to paper when the machine is used
  • Questioned Document Analysis
    • photocopiers and laser printers
      • in photocopier, original is placed on glass and exposed using reflected light to a drum that is covered with photosensitve material
      • image of original exists on drum as invisible positive photoelectric charge
      • negatively charged toner is drizzled on drum where it sticks to the positive image
      • paper with a positive charge passes the drum causing the negatively charged toner to transfer to the paper which is then heat sealed
      • with laser printer - image of the original held in memory of computer is written to the photosensitive drum using a laser
  • Questioned Document Analysis
    • photocopiers and laser printers
      • paper yields clues
        • marks from belts, pinchers, rollers and gears can be matched like toolmarks
      • toner
        • can have unique chemical compositions
        • how toner is placed and fused on paper (ie. clumps, blobs)
      • marks on optics
        • scratches or other marks on glass, lenses or mirrors will leave markings on the printed page that can be matched with the optic
  • Questioned Document Analysis
    • forgery
      • false making or altering of any writing with intent to defraud
      • four types
        • traced
        • simulation
        • freehand
        • lifted
  • Questioned Document Analysis
    • forgery
      • traced can use
        • overlays (like tracing paper)
        • transmitted light (as with a light board)
        • tracing indentations left in the page underneath the original
        • tracing patterns of dots that outline the writing to be forged
  • Questioned Document Analysis
    • forgery
      • simulation
        • involves the copying of writing from a genuine article, trying to imitate the handwriting of the original
      • freehand
        • written with no knowledge of the appearance of the original
        • just writing off the top of your head and passing it off as something else
  • Questioned Document Analysis
    • forgery
      • lifted
        • tape is used to lift off a signature then place it on another document
      • detection of forgeries
        • freehand easiest to detect
        • simulation easy to detect – style not as fluid, more hesitations than “comfortable” writing
        • traced and lifted are easy to detect but identity of forger cannot be determined
  • Questioned Document Analysis
    • counterfeit security measures
      • U.S. currency
        • easy to counterfeit!
        • all paper currency after 1993 has microline printing, nylon security threads and a plastic security strip
        • as of 2000, all paper currency was updated except the $1 bill
  • Questioned Document Analysis
    • counterfeit security measures
      • official documents (i.e. passport)
        • background is printed with intricate pattern of polygons with a color shift in the ink
        • green stars – reflective specks sealed in the paper
        • blue “USA” stamp overlaps photo and background paper
        • three red stars stamped over edge of photo
        • whole page sealed with single sheet of adhesive plastic
        • microline printing in lower right corner
  • Criminal Law
    • serves to define offences under a codified system of laws and punishments
    • where we define what crime is and how it goes about being prosecuted
  • Criminal Law - Homocide
    • murder (malice required)
      • first degree
        • intentional and premeditated killing
        • killing in the course of a dangerous felony
      • second degree
        • intentional, but not premeditated
        • intent to cause serious bodily injury resulting in death
        • death by act creating grave risk of death
        • killing in the course of other mala in se felonies
  • Criminal Law - Homocide
    • manslaughter (no malice required)
      • voluntary
        • killing with the intent to kill or inflict grievous bodily injury but under the influence of passion caused by sufficient provocation
      • involuntary
        • negligent or reckless homocide
        • killing in the course of committing a dangerous misdemeanor
  • Criminal Law - Homocide
    • justifiable homocide
      • self defense
      • defense of others
      • defense of property
      • prevention of felonies
      • arresting a felon
  • Criminal Law - Homocide
    • accidental death
      • duty of care
      • involuntary manslaughter or negligence
  • Criminal Law – Assault and Battery
    • battery
      • intentional or reckless touching of another without excuse or justification
      • does not require significant blow that inflicts bodily injury
  • Criminal Law – Assault and Battery
    • assault
      • an unlawful attempt, coupled with present ability, to commit a battery (such as a missed punch)
  • Criminal Law – Assault and Battery
    • aggravated assault and battery
      • when battery inflicts a serious bodily injury or assault and battery involves the use of a deadly weapon
      • assault with intent to rape
  • Criminal Law – Rape
    • sexual intercourse by a male with a female, who is not his wife, achieved by force or threat of force against the will of the victim
      • force can include drugs administered by the male OR inability of the victim to understand what is happening
      • spousal “immunity” in some old laws has been done away with
      • men don’t rape men – they sodomize
      • women may be charged with rape as a accomplice, (this too is changing)
  • Criminal Law – Rape
    • statutory rape involves sexual intercourse with a minor who is regarded by law as incapable of giving lawful consent to the act
  • Criminal Law – Conspiracy
    • agreement between two or more people, beyond an undercover government agent, to commit an unlawful act, and some degree of intent
      • ultimate act can be impossible to carry out
      • everyone does not have to know everyone else involved
      • all parties must have a common end
      • acts of one are acts of all
  • Criminal Law – Conspiracy
    • for conspiracy, one overt act in furtherance of the crime by any involved party gives liability
      • if one abandons the conspiracy, he is still liable for the conspiracy, but not the resulting act
      • “ overt act” need not be criminal in itself
    • individuals are charged with conspiracy and the actual crime (i.e. murder), the two don’t merge
  • Criminal Law – Burglary
    • at common law, breaking and entering into a dwelling during the night with intent to commit a felony
      • modern code includes
        • any building or similar structure
        • day or night
        • unlawful entry
        • with or without a breaking
      • people get robbed, not houses
  • Criminal Law – Larceny
    • taking the property of another, with knowledge of their ownership, to deprive them permanently or infringe upon their rights in a substantial way
      • petit vs. grand larceny varies in $$$ amount of property
      • one cannot negligently steal
  • Criminal Law – Embezzlement
    • persons who lawfully received possession of the property of another and then wrongfully convert that property to their own use
      • real property can be embezzled
      • does not require intent to permanently deprive
  • Criminal Law – False Pretenses
    • applies to persons who induce others to transfer property to them by means of misrepresentation, which must be to a material past or present fact that the seller know to be false
      • does not include “seller’s talk”
  • Criminal Law – Robbery
    • a larceny with the stolen property taken from the victim in the presence of the victim and with the taking accomplished by means of force or threat of force
      • crime against person and property
    • Does pickpocketing constitute a robbery?
  • Criminal Law – Extortion
    • threat of force or harm used to achieve some sort of benefit to the criminal
      • truth can be used as leverage
      • benefit does not have to be monetary
      • “ blackmailing”
  • Criminal Law – Arson
    • an intentional or reckless burning or explosion of a building owned by another person or, under limited circumstances, of a building owned by the actor
  • Criminal Law – Solicitation
    • agreement to commit a crime
      • hiring individual is just as liable as the actor
      • merges into conspiracy
  • Criminal Law – Aiding and Abetting
    • involved prior to the crime, contributed to the act or induced the act, even if not involved in the act itself
      • one who orders a crime shares the same liability as the actor
  • Careers in Law Enforcement
    • federal law enforcement
    • state agencies
    • city agencies
    • local agencies
    • private sector
  • Careers in Law Enforcement
    • types of jobs
      • investigators, officers, troopers
      • lab positions
      • support positions (clerks, evidence technicians, surveillance operations, photographers)
    • education necessary
      • depends on job description and agency
      • usually college degree to start
      • specialization in a field might be required
  • Careers in Law Enforcement
    • typical application process
      • call agency’s personal department and ask for an application
      • send in and get called for initial interview
      • written exam – much like SAT’s
      • background questionnaire and check
      • panel interview
      • physical
      • fitness test (if in the field)
      • polygraph test