Crime scene reconstruction
Download
1 / 58

Crime Scene Reconstruction - PowerPoint PPT Presentation


  • 259 Views
  • Uploaded on

Crime Scene Reconstruction. Glass . Blood. Laminated Glass .

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Crime Scene Reconstruction' - pekelo


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript


Laminated Glass is made up of a vinyl laminate (PVB) layer bonded together between two panes of glass under heat and pressure. Laminated glass may crack upon impact, however the glass fragments typically stick to the protective inter-layer rather than falling free and potentially causing injury. It breaks exactly like the windshield of your car, cracks but is held in place by the vinyl laminate layer.


Tempered safety glass
Tempered Safety Glass bonded together between two panes of glass under heat and pressure. Laminated glass may crack upon impact, however the glass fragments typically stick to the protective inter-layer rather than falling free and potentially causing injury. It breaks exactly like the windshield of your car, cracks but is held in place by the vinyl laminate layer.


The "heat-treatment" process of tempered glass provides safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards.


Annealed ordinary glass
Annealed/Ordinary Glass safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards.


Glass fracture from bullets
Glass Fracture from Bullets safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards.


Blood stain patterns
Blood Stain Patterns safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards.

  • 1. Low Velocity Impact

    • Droplets

    • Cast offs

      2. Medium Velocity Impact

    • Spatter from weapon’s impact

    • Arterial spurts

      3. High Velocity

    • Spray from weapon exiting body

    • Exhalation of blood


Bloodstain evidence may reveal
Bloodstain Evidence safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards. May reveal:

  • Origin(s) of bloodstain

  • Distance of bloodstain from target

  • Direction from which blood impacted

  • Speed with which blood left its source

  • Position of victim & assailant

  • Movement of victim & assailant

  • Number of blows/shots


Blood spatter
Blood Spatter safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards.

  • Low velocity

    • e.g. free-falling drops, cast off from weapon

  • Medium velocity

    • e.g. baseball bat blows

  • High velocity

    • e.g. gunshot, machinery


Low velocity blood spatter
Low Velocity Blood Spatter safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards.

  • Blood source subjected to LV impact

  • Spot diameter: mostly 4 - 8 mm

    • some smaller, some larger

  • Free-falling drops (gravity only)

  • Cast off from fist, shoe, weapon

  • Dripping

  • Splashing

  • Arterial spurting


Height fallen

Height Fallen safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards.

Single drops of blood falling from fingertip onto smooth cardboard from various heights.

No change in diameter beyond 7 ft.

Adapted from

Introduction to Forensic Sciences,

W. Eckert, CRC, 1997


Angle of impact

80 safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards. 

90

10

60

50

40

70

20

30

14

Angle of Impact

Gravitational dense zone

at lower edge

Adapted from

Introduction to Forensic Sciences,

W. Eckert, CRC, 1997


Point of origin

Origin safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards.

Height above point of convergence

85

60

45

30

Distance from point of convergence

length

Point of Origin

width

Angle of impact = arc sin W/L


Cast off from weapon
Cast-off from Weapon safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards.

  • First blow causes bleeding

  • Subsequent blows contaminate weapon with blood

  • Blood is cast-off tangientially to arc of upswing or backswing

  • Pattern & intensity depends on:

    • type of weapon

    • amount of blood adhering to weapon

    • length of arc


Drip pattern

. safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

Drip Pattern

  • Free-falling drops dripping into wet blood

  • Large irregular central stain

  • Small round & oval satellite stains

.

.

.

.


Drip 2

Blood dripping into itself from height of 1 m (8 drops) safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards.

Drip 2

39


Dripping onto steps
Dripping onto steps safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards.


Wave cast off

Tail of elongated stain safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards.

points in direction of travel

.

Tail of wave cast-off points

back to parent drop

Parent drop

wave cast-off

Wave Cast-off


Medium velocity blood spatter
Medium Velocity safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards. Blood Spatter

  • Blows with weapon (e.g. baseball bat)


Downswing of hammer
Downswing of Hammer safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards.


Cast off from weapon1
Cast-off from Weapon safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards.

ceiling


Overhead swing with bloodied metal bar
Overhead swing with bloodied metal bar safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards.


Cast off pattern how many strikes
Cast-off safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards. PatternHow many strikes?


Cast off pattern ans 4 first strike causes bleeding
Cast off safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards. Patternans: 4 (first strike causes bleeding)

1

2

3


Cast off pattern how many strikes1
Cast off Pattern safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards. How many strikes?


Cast off pattern ans 4
Cast off Pattern safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards. ans: 4

1

(4 spots)

2

(3 spots)

3

(2 spots)

If weapon does not pick up more blood, spatter from subsequent backswings becomes progressively less.

In practice weapon picks up more blood with each successful blow.


Three overhead swings with hatchet
Three overhead swings with hatchet safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards.


Cast off pattern object
Cast-off Pattern safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards. ? Object


Cast off pattern from hand
Cast-off Pattern safety characteristics giving it additional strength, resistance to thermal stress and impact resistance. Additionally, when fully tempered glass breaks it fractures into small, relatively harmless fragments. And markedly reduces the likelihood of injury to people as there are no jagged edges or sharp shards. from Hand





Arterial spurt pattern
Arterial Spurt Pattern target

  • Blood exiting body under arterial pressure

  • Large stains with downward flow on vertical surfaces

  • wave-form of pulsatile flow may be apparent


Small arterial spurt
Small arterial spurt target

spatter

broken pottery



Neck incisions
Neck incisions target

‘Hesitation’ injuries

Probe in carotid artery

Thyroid cartilage


Medium velocity blood spatter point of impact 15 cm in front of vertical target surface
Medium velocity blood spatter. targetPoint of impact 15 cm in front of vertical target surface

6” ruler


High velocity blood spatter
High Velocity Blood Spatter target

  • Blood source subjected to HV impact

  • Fine mist

  • Some larger droplets reach further

  • Gunshot

    • back-spatter from entry wound

    • forward spatter from exit wound

  • High speed machinery


Gunshot back forward spatter

bullet exits foam target

Bullet enters

foam

bullet

Gunshot: back& forward spatter

Bloodstained foam held just above target surface.

Bullet passing L to R just above sheet

Back-spatter

on entry

Forward spatter

on exit


Gunshot back spatter
Gunshot Back Spatter target

  • Arises from entrance wound

  • Passes back towards weapon & shooter

  • Seen only at close range of fire

  • Seen on:

    • inside of barrel

    • exterior of weapon

    • hand, arm, chest of shooter


Back spatter on steadying hand
Back spatter targeton steadying hand


Gunshot forward spatter
Gunshot Forward Spatter target

  • Arises from exit wound

  • Passes forwards in same direction as shot

  • More copious than back-spatter

  • Can be seen at any range of fire

  • Seen on nearby surfaces, objects, persons

    • especially on wall behind victim


Gunshot forward spatter1
Gunshot Forward Spatter target

  • Arises from exit wound

  • Passes forwards in same direction as shot

  • More copious than back-spatter

  • Can be seen at any range of fire

  • Seen on nearby surfaces, objects, persons

    • especially on wall behind victim


Flow patterns
Flow Patterns target

  • Blood flows horizontally & vertically

  • Altered by contours, obstacles

  • Often ends in pool


Transfer patterns
Transfer Patterns target

  • Wet, bloodied object contacts a secondary surface

  • Transfer from:

    • hand, fingers

    • shoes, weapon

    • hair

  • Transfer to:

    • walls, ceilings

    • clothing, bedding

  • Produces mirror-image of bloodied object


Flow pattern
Flow pattern target


ad