Crime Scene Processing Protocol

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• Forensic Science-the application of science to
  laws in a criminal justice system

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Scientific Method

• Process that uses guidelines to ensure systematic
  collection, organization, and analysis of
  information
• 1. Identify problem or question-ex. Examining a
  bloodstain-Is the stain actually blood?
• If it is blood, is it human blood?
• 2. Research scene to answer question-scene
  reports

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Scientific Method

• 3. Hypothesis-untested possible explanation to
  question or problem based on knowledge or
  observation.
• What is the solution?
• 4. Experiment-test hypothesis-hypothesis
  supported by evidence from crime scene
• 5. Collect data-lab analysis of evidence
• 6. Conclusion based on data

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Locards Exchange Principle

• Locard's principle-applied to crime scenes
• Perpetrator(s) of a crime comes into contact with
  the scene
• Every contact leaves a trace

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• Wherever he steps, whatever he touches, whatever
  he leaves, even unconsciously, will serve as a
  silent witness against him. Not only his
  fingerprints or his footprints, but his hair, the
  fibers from his clothes, the glass he breaks, the
  tool mark he leaves, the paint he scratches, the
  blood or semen he deposits or collects. All of
  these and more, bear mute witness against him.
  This is evidence that does not forget. It is not
  confused by the excitement of the moment. It is
  not absent because human witnesses are. It is
  factual evidence. Physical evidence cannot be
  wrong, it cannot perjure itself, it cannot be
  wholly absent. Only human failure to find it,
  study and understand it, can diminish its value.
  '
• -Professor Edmond Locard

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• Purpose of Crime Scene Investigation
• 1. Collection of physical evidence
• 2. Establish crime was committed-corpus delicti
• 3. Reconstruction of crime
• 4. Identification/Connect suspect to crime scene
• 5. Establish probable cause

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1-Approach Scene

• Secure and Isolate Crime Scene
• Secure crime scene with tape and police officers
• Assist victims
• Notes-type of crime, conditions, individuals
  present, exit, entry route
• Determine Scene boundaries
• Walk-through of Crime Scene
• Administrative Worksheet-timeline of events from
  call to release

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2-Record Crime Scene

• Written notes
• Photographs
• Diagram
• Videotapes

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• Seven documents in investigation
• Administrative Worksheet
• Entry/Exit Log
• Narrative Description
• Photographic Log
• Diagram/Sketch
• Evidence Recovery Log-Including Latent Print Lift
  Log
• Crime Scene Release Form

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• Narrative Description
• Description of conditions at crime scene-ex -what
  should be present and is not (victim's car)
• General to specific"
• Methods of narrative - written, audio, video
• Identify evidence
• Point of entry/exit
• Path into and out of area

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Photograph Scene

• Maintain photographic Log
• Progression of overall, medium and close-up views
  of the scene
• When a scale device is used, first take a
  photograph without scale
• Photograph evidence before collecting or moving
  evidence

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Types of Photographs

• Integrity Original crime scene
• Long range Show location from distance
• Medium rangeShow location of evidence
• Closeup 90 degrees to item with measuring device
  (scale) and without
• Photographic log time, date, location,
  description, direction, type of camera and lens,
  weather and lighting conditions, of photos

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Prepare Diagram/Sketch

• Diagram-permanent record of items, conditions,
  distance/size relationships
• Rough diagram-drawn at scene-model for finished
  sketches
• General progression of sketches
• Lay out basic perimeter
• Drawn from two immovable objects
• Position of evidence-outline objects
• Record measurements
• Title, scale (not to scale), Legend, compass
  orientation

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• Crime Scene Diagram
• 1. Dimension
• 2. Distance
• 3. Context
• 4. Relationship among evidence

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• Crime Scene Diagram

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8. Systematic Search for Evidence

• Methodical and systematic search for physical
  evidence to obtain an unbiased reconstruction of
  the crime scene

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PHYSICAL EVIDENCE

• Any items that can establish that a crime has
  been committed or can link a crime and its victim
  or perpetrator

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Types of Evidence

• 1. Direct evidence-first-hand observation-eyewitne
  ss accounts, police video camera, confession
• 2. Circumstantial evidence-Indirect
  evidence-evidence at crime scene that connects
  suspect to crime scene ex. Suspects gun

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Types of Evidence

• Corpus Delicti Evidence establishes that crime
  was committed
• Probative Evidence evidence needed to prosecute
  a case-incriminating evidence
• Exculpatory Evidence evidence that defends
  suspect-exonerating evidence

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Characteristics of Evidence

• Class characteristics properties of evidence
  that are associated with one group and never with
  a single source-ex. Blood types
• Individual characteristics properties of
  evidence associated with a common source with an
  extremely high degree of probability-ex. Matching
  ridge characteristics of two prints, comparison
  of random bullet striations

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Crime-scene search patterns
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Generalities

• 4. Collect and Package Physical Evidence
• Evidence must be handled and processed in
  a way that prevents any change from taking place
  between the time it is removed from the crime
  scene and the time that it is received in the
  laboratory
• Most evidence -collected in PAPER packages
• Druggists fold-paper packet-then put in
  envelope
• Liquid items-non-breakable containers
• Blood stained material-air dry and put in paper
  packages
• Charred debris-airtight containers-prevent
  evaporation of petroleum residue
• Package different items or similar items in
  different locations separately
• Evidence Evaluation Log (EEL)-records procedures
  performed on evidence once removed from scene
• If evidence bags are opened-open along sealed
  edge, tape, sign across tape

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• Evidence
• Submission
• Form

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Labeling-The Big 8

• All evidence labeled with THE BIG 8
• 1-The collecting person's initials
• 2-The date it was collected
• 3-Time it was collected
• 4- complete description of the evidence
• 5-Cat number for this piece of evidence
• 6-Location evidence was found
• 7-Investigating agency's name
• 8-Case/file number
• The big 8 is on all packaging-primary and
  secondary packaging (druggists fold and outer
  envelope)

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5. Maintain the Chain Of Custody
The sequence linking possession of evidence from
collection to disposition-including forensic
examination and admission into court as evidence
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6. Obtaining control standards

• Specimens used as "knowns" must be collected
  against "unknown (Qs) specimens for comparisons
• Unknowns" compared with knowns"
• DNA samples from victims and persons lawfully
  present at time of crime

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7. Submit Evidence to LaboratoryExamination of
Physical Evidence

• Identification-process of determining
  substances physical or chemical identity ex.
  Test for cocaine, blood
• Testing procedures provide expected results for
  comparison
• The number and type of tests are sufficient to
  exclude all other possibilities

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• Evidence
• Submission
• Form

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Examination of Physical Evidence

• Comparison-process of determining if two objects
  have a common origin
• Suspect specimen and standard specimen subjected
  to same test to determine if of common origin
• Selected properties are chosen from suspect and
  standard specimen for comparison
• Determine if originated from same source

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Probability

• Product rule-probability of characteristics
  determined separately and then multiply
  frequencies of characteristics
• Result-overall frequency of occurrence for that
  combination of characteristics
• Probability of two individuals having the same
  fingerprints-one out of 1 x 1060

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8. Ensure Crime Scene Safety

• Potentially infectious materials at crime scene
  -HIV and Hepatitis-protection from health hazards

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Wayne Williams Case Fiber
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Trilobal Carpet Fibers Wayne Williams Case
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It Came Back to Bite Him in the EndTed Bundy Case

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Paint It Black

• Gary Ridgway (Green River Killer) murdered about
  50 people-prostitutes in Seattle
• 20 year hunt-matched paint particles on four
  victims to rare paint at his auto shop
• 2003 -confessed to his role as one of most
  prolific serial killers in American history.

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Oh, CrapPhillip Stroud Case

• There was a 10 billion to one chance that traces
  of dog feces on his shoes were not an exact match
  to dog feces found near victims
• Convicted in 2002-sentenced to life in prison

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Class Evidence

• Cannot assign probability values to comparison
  of most class physical evidence
• As the number of different objects linking an
  individual to a crime increases, the probability
  of involvement increases

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Comparison microscope
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Integrated Automated Fingerprint Identificatio
System (IAFIS)

• National fingerprint database-50 million subjects

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Combined DNA Index System (CODIS)

• DNA profile database
• Forensic index and Offender Index
• Forensic index-unsolved crime scene
  evidence-110,000 profiles
• Offender index-3 million convicted or arrested
  individuals

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Forensic DNA Typing
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Integrated Ballistics Identification System (IBIS)

• Database of bullets and cartridge casing
• Does not positively match bullets fired from same
  weapon-firearms examiner
• Provides list of candidates for comparison
• 900,000 entries

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International Forensic Automotive Paint Data
Query (PDQ)

• Database of chemical and color information of
  automotive paints
• Make, model, year, assembly plant
• More than 13,000 vehicles with database more
  than 50,000 layers of paint

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Envelope containing anthrax spores sent to
senator after September 11th. Bar codes on
envelope by mail-sorting machines contain address
information where envelope was first processed.
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Comparison
bsapp.com

• Most types of evidence require a control with
  which to be compared

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Fingerprinting
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Printer forensics

• Trace documents to specific printers-
  "banding-technique law-officers could use for
  counterfeiting, forgeries
• Identify characteristics unique for each printer
• Designing printers to purposely embed
  individualized characteristics in documents
• Counterfeiters digitally scan currency and use
  color laser printers to produce bogus bills
• Forgers make fake ids, passports

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Video Forensics

• Image Enhancement and Recovery Methods for
  Analyzing Surveillance Imagery
• Image restoration and enhancement tools for
  managing and processing digitized streams of
  video surveillance data.Software-ViTAL (Video
  Tool for Aiding Law Enforcement)-for video
  forensics analyst

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Fractures
Concentric
Radial
bsapp.com
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Direction of Penetration
Radial
Concentric
bsapp.com
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Forensic DNA Typing
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Bloodstain Pattern analysis
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