start by asking
Who
Is involved?
first officer on scene
specialized officer
forensic scientist
forensic identification officer
What
are the processes of forensic identification?
are the disciplines / types?
includes
biological
non-biological
DNA
facial approximation
fingerprint / friction ridge
footwear impression
biological basis
partially
persistent throughout life
unique & never repeated
made of ridge units
deposits include mix of
levels of detail
- overall ridge flow (naked eye)
- characteristics & details (magnifying glass)
- finite details (microscope)
can lead to identification
is fundamental to this field?
Dr. Edmond Locard
"every contact leaves a trace"
can only lead to exclusions
vs.
include
comparison
evaluation
verification
duties include
secure scene
ducumentation
investigation
of evidence
received specialized training
analysis
includes
2D
3D
photographing both require
camera parallel to print
proper scale
impression methods
electrostatic lifter
mylar film
gelatin
impression methods
casting with
dental stone
sulphur
eccrine sweat
sebaceous oil
foreign particles
examination methods
CA glue fuming
use of chemicals
use of forensic light sources
use of filters
same method does not work for everything, need to use different combinations / methods
applies as well
testify in court
duties include
could be
blood
can lead to
blood stain pattern
gives information about
events transpired
sequence of events
HOW as opposed to WHO
different from all other types of investigation
utilizes technologies
video analysis
high speed
time lapse
microscopic
classifications
passive
transfer
spatter
exceptions
from one surface to another
force of gravity acting alone
external force applied to source
ex. cast off pattern, expirated, mist pattern
ex. drip stain, drip trail, pool pattern
greater applied force, smaller stain size
can be caused by
firearms
can possibly give
ex. wipe pattern, swipe pattern
computer models
area of convergence
enhancement
collection of evidence
hypothesize
laser scanning
for documentation
for training/ research
possibly give information for
also an important part of
shooting scene reconstruction
based on
impact location
physical evidence
documented by using
stringing
laser scanners
lidar
then be used for
photogrammetry
videogrammetry
3D models
≠
recreation
based on
witness statements & theories
has less weight in trial
could be
interactive
used with virtual reality
ie. virtual tour
process include
- create likeness
- present to public
- generate new leads
- positive ID
generally not done in other types of forensic ID (except during trials)
how is it done?
manual
digital
American method
clay
advantages include
lifelike texture
can create
different hair models
depends heavily on
audience
cognition (matching)
types include
primed
actively seeking to match
is the ultimate goal / purpose?
present evidence in court of law
same for all types of forensic identification
same as
whether Q & K from same source?
movement
object or mechanism used
urine
semen
skin
hair
number of impacts
combination of knowledge in
anthropology
osteology
anatomy
technology
same for all disciplines of forensic ID
trace evidence
locate using ALS
enhance by using
dilution
insect activity
drying
clotting
lead to alterations
casual
merely passing
also creates
also used in
also used in blood stain pattern analysis
crucial for all types of ID
is it for / is the audience?
the public
ie. facial approximation models
court of law
jurors
judge
prevent contamination
safety & control
to
of crime scene conditions
witness testimony
photography
manual tools
important for all types of forensic ID
oblique lighting for photographing
angled lighting for photographing
establishing "path of contamination"
also used by
by
casting
using
ex.
footwear impression
stringing
bloodstain pattern analysis
shooting reconstruction
used in
used for
scanning tech.
laser
ex.
shooting reconstruction
bloodstain pattern analysis
mapping crime scene
lidar
useful for
light detection and ranging
light amplification by stimulated emission of radiation
aka.
aka.
family member of victim
ex.
tissue depth markers
using
orientation
pattern type
ridge endings
ridge paths
pores
end shapes and angles
edge shapes
examines
examines
examines
depends on substrate
to find area of origin
to help calculate bullet trajectory
Rhodamine 6G
porous
non-porous
whether
tracer laser
blue light
uv
Basic Yellow 40
Ardox
ex.
ex.
vary within limits
by migrating to fingers
through process of
data
being
combined
interpolated
extrapolated
compared
formulated
resulting in
new information
that creates
to find
which is
to help calculate
bullet trajectory
are
's
central dogma of forensic science