Investigating the Crime Scene

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Investigating the Crime Scene
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Crime Scene Objectives

• Solve a crime by understanding the events that
  took place
• How do I document the scene?
• What evidence do I collect?
• Who is connected to the crime?
• This is accomplished by
• making and recording observations
• finding, collecting and examining physical
  evidence
• interviewing suspects, victims and witnesses

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Responding to a Crime Scene

• First responder (usually a police officer)
• Offers assistance to injured persons
• Identifies witnesses and suspects
• Identifies the scope of the scene and secure it
• Documents the conditions of the scene
• Protects the evidence
• Later responders (detectives and/or CSIs)
• Contacts first responder for overview of scene
• Directs the investigation
• Collects evidence and/or statements

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Securing the Crime Scene

• Set initial boundary larger than the scene
• Create a staging or work area outside the scene
• Locate physical evidence for collection
• Create single path in and out of scene
• Document all actions taken by responders
• Personal information
• Actions and statements of persons entering and
  exiting the scene
• Items moved and who moved them

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Securing the Crime Scene
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Processing a Crime Scene

• The lead investigator will get a report from the
  first responder then evaluate the area.
• The investigator then proceeds with an initial
  walk-through to gain an overview and develop a
  strategy for a systematic search and
  documentation of the entire crime scene.
• Search and documentation of the scene with
  photography and sketches while identifying and
  documenting all visible evidence.
• Collection and packaging of evidence.
• Processing for latent prints impressions.

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Processing a Crime Scene
What is each persons role in processing the
crime scene below?
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The Search

• The search for physical evidence at a crime scene
  must be thorough and systematic using a spiral,
  grid, line or zone search.
• The search pattern selected will normally depend
  on the size and locale of the scene and the
  number of evidence collectors.
• Investigators wear gloves and shoe protectors to
  prevent contamination of the scene.
• Begin searches outside or at the point of entry
  or exit and move inward.

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Systematic Search for Evidence
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Systematic Search for Evidence

• Search patterns
• Spiral no physical boundaries
• Grid large outdoor crime scene
• Strip outdoor crime scene where coordinator
  organizes many searchers
• Zone indoor crime scene where different teams
  are assigned small areas
• Wheel circular crime scenes

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Documenting the Scene

• Documenting is the most important and
  time-consuming activity at a crime scene because
• Helps maintain a chain of custody which proves
  nothing was altered.
• It shows who discovered an item of evidence, when
  it was discovered, its appearance, etc.
• It helps the crime scene analyst understand how
  the evidence relates to the overall scene.
• The notes may become evidence in court.
• Notes, photographs and diagrams document the
  condition of the crime scene and the location of
  physical evidence.

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Taking Notes

• Describe the crime scene, the location, weather
  and all physical evidence.
• Make notes in ink, in a bound notebook, with
  pages numbered sequentially.
• Do not erase errors cross them out with pen.
• Make notations in chronological order.
• Evidence is documented by describing
• Type and condition of evidence
• Time of discovery
• Name of discoverer
• Placement, collection, packaging, labeling

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Photography

• Take as many different photos as possible of the
  entire scene and everything in it.
• You can never take too many photos of a crime
  scene. At a death scene there may be 200-500
  shots taken from every possible angle of view.
• Unless there are injured parties involved,
  objects must not be moved until they have been
  photographed from all necessary angles.
• As items of physical evidence are discovered,
  they are photographed to show their position,
  size and location relative to the entire scene.

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Photography

• Take a series of overlapping photos to record all
  possible views of the crime scene and evidence
• Overall interior from all corners or room
• Overall exterior record all structures, paths,
  etc.
• Mid-range show evidence in context of scene
• Close-ups take flash shots with without ruler
• Use a 35-mm single-lens reflex camera and learn
  how to manipulate ALL its settings.
• Archive the original digital images and work with
  copies.
• A photo log must also be created.

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Outdoor Photography
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Photography

• Items included in the photo log
• Date and time
• Camera settings
• Film roll number and exposure number or file name
  and exposure number
• Type of shot
• Distance to the subject
• Brief description

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Indoor Photography
What other photos should be taken in these rooms?
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Photography

• After overviews are taken, close-ups should be
  taken to record the details of the object itself.
  
• A ruler or other measuring scale may be placed
  near the object and included in the photograph.
• Once photographs are taken, the crime-scene
  investigator will sketch the scene.

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Investigating the Crime Scene
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Sketches

• Rough SketchA representation of all essential
  information, evidence and measurements at a
  crime scene drawn at the crime scene.

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Documenting the Scene Evidence

• Sketching
• Accurately record distances between objects
• Make rough sketches not drawn to scale, but with
  adequate information for later finishing
• Sketch the scene from an overhead view
• Must establish two fixed points that are
  permanent objects
• Recognize that a computer professional will
  prepare finished sketches later using CAD
  software

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Sketches
Finished SketchA precise rendering of the crime
scene, usually drawn to scale. This type is not
normally completed at the crime scene.
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Sketches

• Items included in a sketch
• Case identifier
• Date, time, location
• Weather and lighting conditions
• Name of the sketch
• Identity and assignments of personnel
• Dimensions and layout
• Measurements and positioning
• Key or legend
• Orientation
• Scale

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How to Identify Evidence Positions
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Sketches

• Three techniques for determination of position of
  evidence within the crime scene are
• Triangulation measures location of the evidence
  from fixed points
• Baseline draws a line between the fixed points
  and measures the distance to the evidence at a
  right angle from this line
• Polar coordinate method uses a transit or
  compass to measure the angle from the north and
  the distance to the evidence

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Other Ways to Document the Scene Evidence

• Videography
• May be used to complement still photography
• Is the best way to document the overall view of
  the scene
• You must still record the locations of evidence
  in still photos.
• Record a running audio narrative but this must be
  transcribed into a report.
• Leica Geosystems ScanStation can be used to
  create a digital image of the entire crime scene.

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Learning Check

• What important elements are missing from the
  crime sketch below?
• Mark on the sketch or describe the positions
  where photographs of the crime scene and the
  evidence should be taken.

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Beyond The Crime Scene

• The search for physical evidence must continue to
  the autopsy room of a deceased victim.
• The medical examiner or coroner will examine the
  victim to establish a cause and manner of death.
• Tissues and organs will be retained for
  pathological and toxicological examination.
• Also they will provide any physical evidence from
  the body of the victim.

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Beyond The Crime Scene

• The following are often collected by the Medical
  Examiner or Coroner
• Victims clothing
• Fingernail scrapings
• Head and pubic hairs
• Blood (for DNA typing purposes)
• Vaginal, anal, and oral swabs (in sex related
  crimes)
• Recovered bullets from the body
• Hand swabs from shooting victims (for gunshot
  residue analysis)

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Collection of Evidence
This is a photo of a safe burglary. Which items
should be collected and why?
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Collection of Evidence

• Once documented, the evidence must be collected,
  preserved, packaged and inventoried in
  preparation for submission to the crime lab.
• Reference samples should be collected from
  relevant persons or from the scene and are used
  for comparison.
• The selection of items to be collected is based
  on the type of crime scene and the experience of
  the investigator.
• Most of the time there is only one opportunity to
  collect evidence.

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Collection of Evidence

• Impression evidence
• Developed or enhanced by use of specialized
  photographic techniques or chemical developers
• Biological evidence
• Enhanced/developed by chemical means
• Collected with sterile swabs
• Firearms and ammunition
• Located by sight
• Must be rendered safe
• Store in paper envelopes, bags, or boxes

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Collection of Evidence

• Arson and bomb evidence
• Locate by sight and smell
• Place carpet, wood, and absorbent materials in
  clean paint cans and seal lid
• Place flammable liquids in glass bottle with
  tight-fitting lid
• Chemicals and controlled substances
• Locate by visual observation
• Place liquids and solids in screw cap jar or vial

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Collection of Evidence

• Trace evidence
• May be extremely small or microscopic
• Collect by forceps, tweezers, scraping, taping,
  or vacuuming
• Document and collect questioned and known samples
• Work in conjunction with medical examiner for
  homicide evidence collection

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What Evidence Would You Collectand How Would You
Collect it?
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Packaging Evidence

• Each item or similar items collected at different
  locations must be placed in separate containers.
• Packaging evidence separately prevents damage
  through contact and prevents cross-contamination.
• The well-prepared evidence collector will have a
  large assortment of packaging materials and tools
  ready to encounter any type of situation.
• The package should be clearly labeled and sealed
  with evidence tape.

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Packaging Evidence

• Take entire piece of evidence as it is found at
  the scene, if possible.
• Package must preserve and protect evidence.
• Wet blood should either dry first and then be
  scraped or wet blood can be collected on a swab.
• If blood or other biological fluids are stored in
  airtight containers, the accumulation of moisture
  may encourage the growth of mold, which can
  destroy the evidential value of blood.

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Is this evidence properly packaged? Why or why
not?
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Packaging Evidence

• Unbreakable plastic pill bottles with pressure
  lids are excellent containers for hairs, glass,
  fibers, and other kinds of trace evidence.
• Manila envelopes, screw-cap glass vials, or
  cardboard pillboxes are also good containers.
• Ordinary mailing envelopes should not be used
  because powders will leak out of their corners.

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What type of evidence goes in each container?
What shouldnt?
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Investigating the Crime Scene
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Submitting Evidence to The Lab

• Evidence should be sent directly to the lab to
  preserve the chain of custody.
• It may be submitted to the lab in person or via
  mail.
• Chemicals, radiological agents, and explosives
  may be transported via UPS or FedEx.
• Once at the lab, the evidence is placed in
  secured storage areas and logged as to location.

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Chain of Custody
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Chain of Custody

• In court, all evidence will be subject to
  questions about chain of custody.
• The chain starts with the evidences original
  discoverer.
• The chain is broken if movements are not
  documented that may result in evidence being
  excluded in court.
• Preserve the chain of custody by making sure that
  investigator notes completely document everything
  that happens to each piece of evidence at the
  scene and once it is in the lab.

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Evidence and the Fourth Amendment

• Evidence is most often excluded due to Fourth
  Amendment violations.
• Officers must present an affidavit of probable
  cause that criminal activity is taking place at a
  particular location to receive a search warrant.
• Contraband, fruits and instrumentalities of the
  crime, evidentiary items, voice and handwriting
  samples, and conversations can all be obtained
  via warrants.

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Evidence and the Fourth Amendment

• Exceptions to the Fourth Amendment
• Border searches customs searches at the border
  do not require a warrant
• Consent searches persons can voluntarily submit
  to a search but can rescind it at any time
• Search incident to arrest persons and the area
  under immediate control can be searched during a
  lawful arrest
• Plain view doctrine officers can seize
  contraband and evidence that they can see from
  legal vantage point
• There is NO murder scene exception

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Evidence and the Fourth Amendment

• Exceptions to the Fourth Amendment
• Emergency exceptions officers can enter premises
  without a warrant if they have reasonable
  suspicion that an injured person is inside
• Open fields no expectation of privacy
• Stop and frisk officer may pat down a suspicious
  person who may be armed and dangerous
• Vehicle inventories may need to search the
  vehicle immediately if the driver or other
  occupant is arrested

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Evidence and the Fourth Amendment

• Mincey v. Arizona (1978)
• Police conducted an undercover raid of a
  suspected drug house.
• An officer and three suspects were shot.
• The premises were searched extensively over 4
  days without a warrant.
• The court overturned the conviction The offense
  did not merit a warrantless search because the
  evidence would be not lost while a warrant was
  obtained.

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Evidence and the Fourth Amendment

• Michigan v. Tyler (1978)
• It involved a fire at a furniture store.
• Investigators conducted several searches,
  including some well after the fire was out.
• The convictions were overturned The later
  warrantless entries were not part of the initial
  emergency circumstances.
• Officers must obtain a search warrant before they
  conduct a careful, detailed examination of a
  crime scene.