Geberth Collection of Evidence

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s13206l
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146714
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Geberth Collection of Evidence
Updated:
2012-04-10 04:02:20
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Senior CSA Test
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Geberth Chpt. 17 Collection of Evidence
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  1. Physical evidence
    • any tangible article, small or large, which tends to prove or disprove a point in question. It may be used to:
    • reconstruct a crime
    • ID participants
    • confirm or discredit an alibi
  2. In order for physical evidence to be introduces in a trial, an artical must:
    • be properly ID'd
    • show proper chain of custody
    • be material and relevant
    • meet all legal requirements
  3. Guidelines for proper collection and disposition of evidence
    • ea. pc. of evid should be marked to show orig. position and location
    • ea. article should be marked distinctively by the searching officer to ID the person who found it
    • ea. item should be described exactly and completely with case numbers and date and time of collection
    • ea. packg should be sealed ot retain evidence and prevent unauthorized handling
    • ea. pc. of evid. should show proper disposition--police dept. lab, property clerk's office, FBI lab
    • proper record should be kept regarding ea. pc. of evid. showing chain of custody
    • ea. item should be photo'd before it's collected, to include long-range and close-range
  4. Evidence ordinarily falls within 3 distinct categories:
    • body materials
    • objects
    • impressions
  5. Blood--Lrg Amounts/Pools
    • use an eyedropper or hypodermic syringe to collect the fluid and transfer to a sterile container
    • transfer immed. to lab or refrig specimen (DO NOT FREEZE)
    • in some instances add sodium azide or EDTA to prevent spoilage
  6. Blood--Small Amts of wet
    • use 100% cotton swab, #8 cotton thread, or gauze pad to collect specimen
    • allow swab or gauze to air dry
    • place in sterile test tube or other clean container
  7. Bloodstains Dry
    • Nonporous surface--if sufficient amt., it can be scraped from surface with clean razor blade or sterile scalpel into sterile container
    • Porous surface--collect and submit the article as found and wrap in separate and sterile container (if too big remove portion of item)
  8. Dry Bloodstains--Traces
    • moisten a 100% cotton swab or gauze pad with distilled water (obtain control sample)
    • stain will soften and soak into swab or gauze pad
    • allow to air dry
    • place into steril test tube or container for lab
  9. Next to blood, ________ is the physicological fluid most commonly discovered at homicide crime scenes.
    Semen
  10. Semen--Wet Stain
    • swab or wash
    • draw fluid into an eyedropper or hypodermic syringe
    • place in sterile test tube
    • use swab or gauze pad for sampes of smaller quantities which are still moist
    • allow to air dry and place in sterile container
  11. Semen--Dry Stain
    • will have stiff "starchy" texture
    • if on clothing, submit entire article
    • on body, using gauze pad moistened with distilled water, gently remove stain and place in sterile test tube or container after allowing to air dry
  12. Urine
    • remove by eyedropper or gauze pad
    • place in sterile test tube or other container
    • if on clothing, submit entire article
  13. Spittle or Saliva
    • Remove with eye dropper or gauze pad
    • Place in sterile test tube or other clean container after drying
  14. Feces--Lrg Amt
    • remove with small clean shovel
    • allow to air dry
    • place in sterile container
  15. Feces--Small Amt
    • remove with swab or gauze pad moistened with distilled water
    • then air dry or scrape into container
    • place in sterile test tube
  16. Vomit
    • remove with eyedropper or small shovel depending on amt.
    • place into sterile container
  17. Urine, saliva, feces, perspiration, ear wax, nasal mucus, etc. can be typed into the same grouping as blood from an individual who is a _________, approx. 80% of population
    Secretor
  18. Tissue
    • remove with tweezers
    • place in a glass container or sterile test tube
    • forward to med. examiner
  19. Hairs and/or fibers can:
    • help determine the extent of crime scene
    • place the perp at the scene
    • connect the suspect to a weapon
    • corroborate statements of witnesses
    • determine the rout to and fro the scene
    • be located in any number areas involved in the homicide (vic, scene, weapon, tool, vehicle, clothing, suspect)
  20. Determinations from Hair
    • species
    • race
    • location of growth
    • treatment
    • how it was removed
    • disease and or damage
    • genetic info (blood type from shaft, other genetic markers and sex from pulled hair roots)
  21. It is recommended that a sample of hair from __________be obtained in all homicide cases
    various parts of the body
  22. Sampling comprises approx _________ pcs. of hair. Hair removed from head should be taken from ____________. Then the roots should be ___________.
    24-48; front, back, right, left, top; air dried
  23. Collection of Hair
    • use oblique lighting
    • gather by tweezers being careful not to bend or break
    • masking or scotch tape can be used
    • place in sterile container and seal (folded paper or envelopes can be used)
  24. Conclusions from Hair Samples
    • did not come from unknown hair source
    • could have come from known hair source
    • sampling too limtd. for meaningful comparison
    • no conclusion
  25. Bullet Collection
    • bullets should be collected without damaging or marking the rifling
    • bullets embedded in doors, trees, walls, etc. should be removed by taking out a portion of the object in which the bullet has become lodged rather than by probing or digging
    • should be examined for blood or other materials before packaging
    • should be marked on the base or nose
    • ea. bullet should be packgd separately to prevent cross-contamination or accidental abrasion of rifling marks
    • packg should be marked to show ID and location of discovery
  26. Discharged Cartridge Cases or Cartridges
    • CC should be marked on the inside wall by the mouth end or as near to the opening as possible
    • never mark CC on or near the end
    • always consider the possibility of fingerprints on sides of CC and take appropriate measures to preserve them
    • packg in separate containers with proper documentation
  27. Shotgun Shells
    • plstc or paper should be handled in same way as other CC
    • can be marked on metal side part of CC
    • never mark on base of shot shell CC
  28. Live Cartridges
    • examine for fingerprint evid prior to marking
    • mark on side of cartridge
    • packg, indicating the location of recovered rounds
  29. Shotgun Wadding
    • Recover and submit
    • place in separate container
  30. Weapons
    • photo and examine for FP
    • examine for any serology or other trace
    • place in special container according to size
    • forward to serology or crime lab for further analysis
  31. Firearms
    • photo in orig position
    • examine for FP
    • examine for any serology
    • unload and render safe before transporting
    • packg individually in appropriate container (suspend by string thru trigger guard, or if long gun, lay weapon across container in notches at ea. end of the box)
    • indicate finish, brand name, model designation, serial numbers, caliber, and number of shots the weapon is capable of firing
    • mark for ID: revovlers--on frame, barrel and cylinder; rifles and shotugns--on receiver, bolt, and barrel; semiautomatic weapons--receiber, slide, barrel, and any clips
  32. Examination of Fibers will indicate origin as follows:
    • vegetable--cotton and hemp
    • animal--wool and mink
    • mineral--glass wool and asbestos
    • synthetic--nylon and orlon
  33. Examination of Fibers will determine if fiber is similar to the ______.
    control sample
  34. Collect fibers as follows:
    • forceps, tape (most practical), or vacuum sweeping (least desirable)
    • place samples in individual containers from ea. area gathered, mark appropriately, forward to lab
  35. Fabric can be examined to determine:
    • color
    • type of cloth and fiber
    • thread count
    • direction of fiber twist
    • dye
    • (class and individ. characteristics can be obtained from frags of fabric by fitting the evid pcs into its source)
  36. Cig Butts
    • collect with forceps or tweezers and insure dryness
    • place into separate containers to prevent contamination
    • containers should be marked appropriately
    • forward to serology
  37. displaced furniture
    • examine for FP and or serology
    • useful in crime reconstruction
  38. soil
    • color may be distinctive
    • minerals can be distinctive
    • baterial profiles can be distinctive
    • vegetation can be distinctive
  39. tools
    • examine for FP and serology
    • may contain traces of certain materials that wer to be matched up with known samples
    • portion of tool to be matched must be protected
    • broken tools can be fracture matched for ID
    • never try to fit tool into tool mark or match broken pcs.
  40. clothing
    • stains on clothing may match stains from scene, vic, or suspect
    • suspect's clothing may contain blood similar to the vic's
    • vic's clothing may contain saliva and or seminal fluid from perp
    • hairs or fibers may be present on clothing that match similar hairs or fibers from particular scene or location or from vic
    • tears or cuts in clothing made by weapon can be matched to show position of vic at time of assault
    • deposit of GSR on clothing can be analysed to determine the approx distance from which the gun was fired
  41. documents
    • primary consideration in handling is preservation of FP
    • collected by using tweezers or forceps
    • ea. item should be placed in a sparate packg. (clear or see-thru is best)
    • if see-thru packgs are not available, object can be photocopiedusing forceps to place the object on machine and back to envelope
    • marking depends on type of examinations to be conducted
    • should not be folded
    • examine for LP
    • saliva on envelopes can be blood-typed and somtimes analyzed for sex origin
  42. Latent Print Processing on Porous Materials
    • 1st--iodine fuming--reacts with oil or fatty fluids
    • 2nd--ninhydrin--reacts with amino acids in perpiration
    • 3rd--silver nitrate--reacts to salt in perspiration when exposed to strong light
  43. Glass
    refractive index proves that the known sample and the evidence may have come from similar source
  44. Glass can show __________ and ________ of bullet holes thru glass by examination of ________ and _______ fractures and may prove important in reconstructing the crime.
    direction and sequence; radial and concentric
  45. Glass collection
    • small pcs. should be place in vial or pill box
    • larg. pcs. should be placed in sturdy cardboard box with proper padding/protection
  46. Latent print powders __________ interfere with serological analyses.
    do NOT
  47. Ninhdrin sprays and other chemical means ______ interfere with serology tests.
    may
  48. Plastic prints
    impression occur when the finger touches or presses against soft pliable surface such as putty, gum, etc.
  49. Visible prints
    occure when fingers, palms or feet which have been contaminated with foreign substance come into contact with clean surface and are pressed onto the surface leaving a print
  50. Latent print
    occur from the natural skin secretions such as perspiration, when grease or dirt is mixed with it then a stable print may be deposited on the surface
  51. Powder processing
    • a small amt of powder is poured onto a clean pc. of paper
    • brush is drawn across the powder and then tapped with the finger to remove excess
    • surface of object to be searched is then lightly brushed with curved strokes to locate prints
  52. Powder __________ to the ridge structure of the print, being careful not to rub the print too hard.
    parallel
  53. The advantage of magnetic powder is that there is __________ left on the object.
    no mess or excess powder
  54. Preservation of FP
    on homicide scene, prints should be photo'd before attempting to lift them; use 1X1 fingerprint camera
  55. Chemical processes
    iodine fuming, ninhydrin, and silver nitrate. further more, there have been some remarkable results in developing latent prints by use of the laser
  56. The __________ is the most common impression left at or near the scene of a crime.
    footprint
  57. A _________ is formed when the foot or sole and heel of a shoe becomes contaminated with some foreign substance, such as blood, paint or dust. A ____________ is formed like a tire track, when the foot or tire treads are pressed into some type of moldable material such as dirt, clay or snow.
    foot print; foot impression
  58. Collecting Impressions
    • clean of foreign matter
    • enhance with lighting
    • scale
    • photo
    • cast--using 5 lbs plaster of paris, mixing container, stirring stick, reinforcement matrials, shelac or plastic spray, oil spray; clean out loose material, plastic spray to fix soil, build form, pour plaster, add reinforcement sticks
    • collect soil sample
  59. Preserve dust prints
    • photo 1st
    • use special lifter placed sticky-side down over impression,
    • press on lifter,
    • and then remove lifter
  60. When the original tool mark can't be collected
    • photo (long shot and 1x1)
    • cast with silicone rubber after spraying surface with release agent
  61. Bite marks may be considered as ____ marks.
    tool
  62. Bullet holes in wals/furniture
    • photo
    • examine trajectory
  63. Bullet holes in clothing
    • photo
    • safeguard for examination for GSR
    • wrap (do not fold) and place in proper container
    • direction can be ascertained with color (Harrison) test
  64. Newly damaged areas
    • photo
    • examine for any serology
    • examine for any FP
  65. When unraveled, a molecule of DNA is approximately ____ in length
    6 ft.
  66. Watson and Crick in 1953 determined DNA to be a ______ composed of pairs of purine and pyrimidine bases.
    double helix
  67. DNA is made of nucleotides composed of
    sugar, phosphate group, and a base
  68. Four bases are two (2) purines, ________ and __________, and two (2) pyrimidines, _________ and ____________.
    adenine (A) and guanine (G) ; thymine (T) and cytosine (C)
  69. Adenine binds with __________; and Guanine binds with ___
    Thymine; Cytosine
  70. The polymorphic junk DNA regions are known to repeat themselves over and over again like a stutter and are called ____________
    Variable Number of Tandem Repeats (VNTRs)
  71. STR stands for _________.
    Short Tandem Repeats
  72. Everyone uses ____________locus probes for DNA profiling
    single
  73. In 1985, Kerry Mullis developed PCR or ____________________.
    Polymerase Chain Reaction
  74. Three techniques are used by forensic scientists to extract DNA
    • organic extraction,
    • nonorganic extraction
    • and the chelex extraction--only the chelex is unsuitable for use with the RFLP test
  75. RFLP Test
    Restriction Fragment Length Polymorphisms

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