test one Flashcards
forensic science is also known as
criminalistics
sir arthur conan doyle
physical detection methods
Sherlock Holmes
Mathieu Orfila
Forensics toxicology
Calvin Goddard
1891-1955
comparison microscope bullets come from from specific guns
tool marks on bullets
Edmond Locard
1877-1966
every contact leaves a trace
cross transfer of material causes exchange of microscopic materials (fibers, hair, pollen, plant, and soil)
shows duration and intensity –> struggle
Hoover
1932 –:> national forensic lab to support law enforcement
California oldest forensics lab
forensics entomology
insects
aid in determining time of death
Rigor mortis
muscles relax and become rigid
Liver mortos
Blood drains downwards because of gravity which causes bluish tint
Algor Mortis
change in temperature to room temp
demonstrates a general time of death
search methods
spiral search (going in a circle)
Strip/ line search (snake)
Grid method (snake but more intense)
Quadrant/ zone search (breaking it up)
Direct evidence
proves a fact
eyewitness, camera evidence, physical object
Indirect evidence also known as
circumstantial
Individual evidence
linked to a single source
best
fingerprints
handwriting
DNA patterns
Tears
Class evidence
narrows an identity to a group of people
Blood type (narrows but not individual)
Handgun type (not specific murder weapon)
Seven S’s of Crime Scene
Secure scene- first responding police check safety and preserve evidence
Separate - witnesses cant talk to each other
Scan - primary and secondary crime scene
Seeing- overall photos and close up
Sketch - rough sketch and neater copy of Crime scene drawn to scale
Search - grid, zone/quadrant, line/strip, spiral
Secure evidence - properly package, seal, and label evidence
Hair functions
protection
eyebrow and eyelashes
hair in nose and ears
thermoregulation
sense organ
how many hairs are shed daily
250 hairs
100 head hairs
Hair without follicle identifiable
can not be identified
Arrector pilli muscle
goose bumps
Sebaceous gland
sebum lubricates skin and hair
Vellus hair
shorter and thinner found on body
Terminal hair
longer and thicker
Human hair
same morphology
Hair is made up of
keratin
Hair follicle
where hair grows out of
Shaft three layers
cuticle- outer
medulla- middle
cortex- core
coronal scales
crown
rarely found in humans
spinous
triangular
never found in humans
imbricate
puzzle pieces
flat
commonly found in humans
coretex
contains melanin
color shape and distribution of melanin helps compare hair
medulla
medullary index measures diameter of hair
continuous- Asian
interrupted - animals
fragmented - African/ European
absent - African/ european
animal hair identification
medullary index and shape, scale structure
lanugo
fetus hair
Anogen phase
hair is actively rowing
catagen
at rest and not growing
Telagen phase
most often found
sheds the most
Aprocrine gland
sweat gland associated with hair follicles
Eccrine gland
sweat gland on the hands and feet
dactylography
study of fingerprints for identification
Who developed the classification system and what is it called
Sir Francis Galtin
Sir ER Henry
Galton Henry System
AFIS
automated fingerprint searches and storage
collects for criminal check s and employment, licences, and social services
has gotten more accurate over time
Friction ridges/ finger prints
connected units of small raised ridges of the skin
formed at 10 weeks
will not change unless you try to change with acid
How do finger prints develop
basal later cells grow faster than layers above and below which causes it to fall and fold into shapes
protected by epidermis
whorls
most complex
circular patterns
core
what examiner is looking for
center of whirl and loop
Minutiae
called this because the details are so minute and small
“uniqueness” of an individual
primary basis for fingerprint identification
No two individuals have more than 8 common minutiae
Twelve match guideline
two fingerprints match –> there are at least 12 or more matching minutiae
Patent (visible)
clearly recognizable fingerprint that needs no processing
transfer of oils/ other secretions onto a surface
latent
transfer of oils/ other secretions onto a surface
not visible without other processing –> development/enhancement
powder dusting
primary method of visualizing fingerprints
ninhydrin
lifts prints from paper and cardboard
chemical that bonds to amino acids in fingerprints to produce a blue or purple color
takes 1-2 hours to develop
last 24-48 hours
cyanoacrylate fuming method
also known as the super glue method
super glue heated makes a fume that turns a print off white colored
silver nitrate
reacts to salt deposits in sweat
need to be photographed and moved away from a light sourc
iodine fuming
dirty brown colored print needs to be photographed quickly
plastic prints
also known as impression or indentation print
impression left in soft material
clay, putty, wax, tar, butter
questions answered through botanical evidence
- who was with the victim, at the crime scene, or at the time of death?
- what did the victim eat before dying?
- when was the crime committed? When was a specific person, vehicle, or article at a crime scene?
- How long has it been since the victim died –> Postmortem interval? How long was the body buried?
First mention of forensic botany
Plato’s Phaedo of 399 BC
Socrates self administered death sentence of poison hemlock
legal acceptance of forensic botany
trial of Richard Hauptmann
kidnapped and murdered Charles Lindbergh’s son
Training for forensic botany
1993 at quantico
assemblages
groups of plants usually dominated by one species
assemblages share the same habitat requirements
soil type
wind
moisture
latitude and longitude
sunlight
altitude
cellulose
can’t withstand digestion
can estimate postmortem intervals –> degree of digestion
pollen grain
male reproductive structure of a seed plant
spore
reproductive structure of algae and fungi
palynology
study of pollen and spores
pollen and spores
- microscopic
- resistant cell wall
- last for decades, useful for investigations
- jagged edges attach to hair, blankets, and clothing
non seed plants
disperse spores
ferns
mosses
seed plants
predominant land plants
cones or flowers
gymnosperms
oldest seed plants
conifers –> pines, first, and other evergreen plants
angiosperms
flower plants
produce fruit
include corn, oaks, maples, grasses
found at most crime scenes
flower
reproductive unit of an angiosperm
pistil
female part of flower that produces egg
stigma
part of pistil where pollen ends
style
the pollen grain falls through this to get to the ovary
stamen
male reproductive part of the flower responsible for pollen
filament
elevates the anther
anther
produces pollen
endospores
cause diseases
anthrax
botulism
how do fibers differ
cross sectional shape
surface contour
color
length
diameter
natural fiber
exists in its natural state
most likely cotton
manufactured fiber
man made
rayon
acetate
nylons
polyesters
acrylics
Plants/ vegetables
oldest fibers known to us
better ability to absorb moisture and are very comfortable
cotton
Animal fibers: Hair
diameter and scale protrusion
camel, alpaca, goat (cashmere, mohair), rabbit (angora) llama
brushed out, clipped, shed
brushed, shed, clipped
wool
wool is most common
finer wollen fibers –> clothing
coarser woolen –> carpet
fur
skin is treated
remains flexible and retains fur
webbing
silk
collected from cacoons
long
mineral fibers
asbestos
Man made fibers characteristics
color
size
shape
microscopic appearance
chemical composition
dye content
oxidation tests
burn the fibers to evaluate ash, behavior, and smells
physical characteristics can be examined by
calculating density
chemical decomposition tests
oxidation tests
direct transfer
directly from victim to suspect or suspect to victim
secondary transfer
victim has fibers picked up from elsewhere and transferred to the subject
or suspect to victim
