other marks

• types

  palm

  finger

  shoe

  foot

  tyre

  bite

  lip
• evidential value

  size

  pattern

  mould

  damage

  wear
• recovery

  casting for indents

  lifting for imprints
• casting

  dental for shoe and tyre marks

  silicone for finger and toolmarks
• enhancement

  optical

  chemical

  physical
• characteristic

  class (common)

  individual (unique)
• PPE

  Physical pattern evidence
• source

  this can be personal such as palm or footprints or it can be from other objects such as tyre marks or firearm
• formation

  they can be formed from striation which is when a trace is left by rubbing against a receiving surface for example tool or barrel or it can be left via impressions which is physical contact
• impression

  this can be by imprints which are 2d, found on hard flat surfaces due to the deposition of material or by indents which is 3d found on soft surfaces and are deformations
• example of positive print

  fingerprint in blood
• example of negative print

  fingermark left by powder enhancement
• types of marks

  imprints (positive or negative)

  indents
• what is ppe

  patterns that have been transferred from a donor to a reciever surface via physical contact
• importance of ppe

  left easily and unintentionally

  provides evidence to identify criminal, objects used or establish association
• preservation at the crime scene

  photos should be taken at every step, before enhancement and sampling
• casting a shoe print using dental stone in mud


  use a metallic frame to prepare and spray with lacquer is needed

  gently pour for casting
• casting a shoe print in snow

  use snow print wax
• casting a tool mark using silicone


  apply cast on both sides of frame

  remove after it hardens
• casting finger mark using sta seal


  apply base gel

  apply catalyst

  remove to reveal print
• lifting

  electrostatic

  adhesive sheets made of gelatine
• electrostatic lifting

  lifting dust on to a lifting film eg dusty shoe print
• adhesive sheets made of gelatine

  mechanically lift dust from planar surfaces
• optical

  photographs
• physical

  physical interaction between mark and colourful revealing agent (usually powdering)
• chemical

  chemical interaction between Mark and staining reagent that leads to formation of colour complex
• blood staining agents

  diaminobenzidine is brown

  fushin acid is red

  amino black

  tartrazine is yellow
• class characteristics

  size

  pattern

  mold
• individual characterisitcs

  damage

  wear
• procedure for comparison

  use class for linking purposes

  use individual for narrowing the scope
• types of conclusion

  non-conclusive, mark lacked sufficient characteristics

  exclusion, inexplicable differences

  supports individualization, lack of inexplicable differences but the mark has sufficient characteristics
• imprint


  positive = deposited on to surface

  negative = removed from surface