Zusammenfassung der Ressource
Forensic Science and
Detection Methods
- Tool Marks and
Impression Evidence
- Lifted using casting
- 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
- Case Studies
- Sarah Payne