What is Forensic Science?
Application of science to criminal and cival laws that are enforced by police agencies in our justice system
What are the major questions forensic science seeks to answer?
What, When, Where, How
Types of evidence and questions they can answer?
Who didn't or did do it but never why.
1880's to 1900's
bertillon anthropometry applying scientific method on a human identification such as measurements known as the bertillion measurements
1930's
fingerprints first became discovered but wasn't used nation wide till the 50's and 60's
1960's
Teeth odontology; depended on xrays
1970's
blood type A,B,O,AB,+/-
DNA
Doxyriloon ucleic acid genetic information stored in almost every cell of you body
Loci
addresses on the DNA
Codis
Law enforcement looks at 13 addresses
1800's
physical match such as footprints, cigaretts/tobacco, paper
late 1800's
trace evidence- hair/fiber, dirt/soil,
20 century
paint, glass, firearm/bullistic analysis developed by the rifle barrels, drugs, and computer
Divisible matter
matter divides into smaller components when force is applied. These smaller components retain biological, chemical, and or physical properties of source material
Wayne Williams
The Atlanta Child Killer 1981
Accused of two deaths of African Americn males in Atlanta Georgia and later blamed for 23 of 30 homicides, convicted for 2 adult murders
Ku Klux Klan may have been involved in child murders
(Atlanta Child Murderer); misnomer
Will West
had the same bertillon measuements as another prisoner serving a life sentence for murder; proved the Bertillon measurement wrong.
Components of compound microscope
ocular lens, objective lens, stage, iris diaphragm, condenser, light source, and fine and course adjustment knobs
Preparation of wet slides
1. Place the specimen on the center of the slide 2. Put 1 or 2 drops of water on the specimen 3. Cover with coverslip
evidence analyzed with a compound microscope
bacteria, hair, fiber, anything that can see through an object and see the medulla
Components of stereomicroscope
eyepieces, diopter, arm, stage, stage clips, focus control
types of evidence analyzed with stereomicroscope
used to view specimens that are visible to the naked eye such as insects, crystals , circuit boards and coins.
Structure of hair
Cuticle is the outer layer, cortex is the main shaft, medulla is the innermost layer
animal vs. human hair
animal: pigmentation denser medulla, change colors, thick medulla, petal cuticle
human: pigmentation denser cuticle, can't change colors randomly, thin medulla, flat cuticle
growth phases of hair
Anagen: growing phase (90%), 6-7yrs long. Catagen: transitional phase. Telogen: resting phase (shed w/ hair brushing).
questions hair can answer
age, if infant or non infant; body location pubic vs head hair; ethnicity; toxicology
Napoleon's hair
1960's hair sample of the head. neutron activation analysis; aresenic; exposed to arsenic for the six months leading to his death in very high dosseges; known as chronic arsenic poisoning
Natural Fibers
a fiber that comes from plants or hair of animals
Synthetic Fiber
A fiber made from a man-made substance such as plastic
polymers
molecules made from repeating units of identical or nearly identical compounds called monomers
refractive index
measure of how much the speed of light is reduced inside a medium such as glass
structure of paint
manufactered product that contains pigments or other elements thats applied wet and drys to a hard finish;
pigment
provide or hide color
additives
binders: help support pigment/adhere to surface; Filler spread out pigment into even coat
Solvent
least useful-gone; medium in which pigment and additives are suspended and should readily evaporate to leave a dry coat not disolved; very low boiling points.
Layers of Paint
Clear coat, base coat, primer
Clear coat
clear polymer thin to protect the base coat from damage
Base coat
Layer that contains pigmentation and additives; thin
primer
main surface layer to show off the base coat very texured; most prominent
pyrolysis gas chromatography
Used to analyze solid particles like paint, fibers, and plastics. Breaks down solid materials by heating.
Tempered safety glass
*side & rear window of automobiles
*breaks into small squares rather than sharp shards
*Thermocycling
*RI factor changes greater
laminated glass
glass made with plates of plastic or resin or other material between two sheets of glass to prevent shattering
Becke lines
glass placed in liquid and viewed under microscope (low power, etc) if the liquid refractive index (R.I.) is different from fragment, thena halo-like effect (Becke line) occurs
four classes of drugs
1) depressants 2) narcotics 3) stimulants 4) hallucinogens:
Hallucinogens
psychedlic drugs, such as LSD, that distort perception and evoke sensory images in the absence of sensory input; Ecstacy
Stimulant
a drug that increases the action of the central nervous system, the heart, and other organs; Meth
Depressants
Slow down respiratory cardio and central nervous functions;Barbituates-sleep agents, trumpoilyers- anti psychotic sleep indusing; alcohol
Preparation methods of methamphetamies
p2p 1970's to 1990's h2N-CH3 Methylamine 1-2% of meth cooking is by this method
Drug Class Schedule I
high potential for abuse and no legit uses ; heroin, LSD, etc...
Drug Class Schedule II
High potential for abuse and have medical uses; morphine, hospitals/clinical drugs
Drug Class Schedule III
Low potential for abuse; prescription drugs
Drug Class Schedule IV
Prescription drugs; controled for non abuse factors
Screening vs confirmatory tests
Confirmation test gas chromotography, IR; GC- MS gas chromatography mass spethoscopgy; Color Test; produce distinct color in presence of 1 class of drugs
Dr. Shipman
Will left granting him Kathleen Grundy's Money
Lethal Quantity of morphine found in body
All were ederly women found laying down or sitting down, fully clothed
about 236 victims in 24 years
hung him self
Gas Chromatography
chromatographic procedure in which a mixture of gases or highly volatile liquids is separated using a carrier gas passing through a solid, or viscous liquid on a solid support, packed in a column