If can match tool to
several crimes ->
builds intelligence
Casts analysed
using comparison
microscope
test mark v.s.
suspected mark
from scene i.e.
known v.s. unknown
Rising need for a tool
mark database?
Class characteristics
Individual Characteristics
Size of head of the screwdriver;
type of instrument used
damage; metal striations; colour
(i.e. has item been painted?)
Types of tool mark
static/compression (indented)
Dynamic/grinding (slides across surface)
Cutting tool marks (combination of
compression/sliding)
Multistroke i.e. saw
Manufacturing -> striations due to manufacturing process
Very common in
volume crime -> not
utilised to the best
of its ability
Interpretation - strong evidence to refute/corroborate
that a particular tool made a particular mark
Footwear -> Cinderella searching i.e.
forensic podiatry => usually classed
as associative evidence
Very neglected form of evidence i.e. no database -> shoes change
regularly (based on style or fashion -> population demographics)
Can confirm or
refute stories
3D Impressions -> may not get individualising details -> can preserve with hairspray
2D impressions -> ESLA; gel lifts; powders
Types of class/individual characteristics: temporary accidental (i.e.
a stone); damage defects; mould anomaly/defect/ design variation
Eliminate police officers/paramedics etc. then document remainder of marks
Can determine: shoe size; gait; number of
people present. Also useful in tracking
Footwear from all suspects usually seized in most crimes to be printed
DNA and DNA Analysis
Bodily Fluids
Light
Forensic provision,
processes and application
Observations -> Hypotheses -> Inferences.
Limits of knowledge => bias and error
Trace
Type
4 main categories: Hair and Fibres; Glass; Paint;
Biological evidence -> but there are lots more!
Location and Amount
Transferance and Persistence
Circumstances
Looking for links between: Victim +
scene/Victim +suspect/Suspect +scene
Want to establish
relationships and contexrt
Significance and
probative value
LOCARD'S PRINCIPLE OF EXCHANGE
History
The Washing Away of Wrongs (1247) - Song
Chi -> first documented use of forensic
entomology -> basics of forensic process
Philosophy of the Enlightenment -> scientific revolution
between C16th and C18th. Move away from religious
doctrine to science and evidence -> better society!
Epistemology v.s. Ontology -> theory of knowledge and
its methods, validity and scope v.s. the nature of being