Exam 1 Flashcards
The Scientific Process
- Observation
- Ask Question
- Hypothesis/Prediction
- Experiment(s)
- Analysis of Results
- Conclusion
Paradigm
Tested and researched so much that it now is a
foundational concept for understanding systems
Theory
Highest level of knowledge in science. Based on hypotheses that withstood multiple, rigorous testing without being disproven
Hypothesis
A possible explanation for a set of observations. Not a random guess or opinion and is testable.
Deductive Reasoning
Applies general principles to reach specific conclusions.
Inductive
Assimilates specific information
to build general principle.
Deduction in Forensic Science
When someone fires a gun, GSR
is deposited on hand,
GSR contains nitrates,
Suspect X tested for GSR
positive, Deduction: Suspect X recently discharged a firearm. If the premise is true, the
conclusion must be true.
Archimedes
Father of Forensic Science. Calculated Density
(water displacement).
Hans Gross
- Created field of Criminalistics
- Criminal Investigation 1891
- Handbook on Forensic Science
Anthropometry
The study of Body Measurements.
Density
= Mass/Volume
We can measure volume
then calculate density
Alphonse Bertillon
Body Measurements. “Father of criminal identification.”
Sir Frances
Galton
- 1892: the lexeme “fingerprint”
- First definitive study &
classification of fingerprints - 1903: used in US for criminal ID
The Marsh Test
Mix suspected fluid (has arsenic)
with sulfuric acid & zinc
↓
Arsine gas is formed
↓
Gas heated & condenses on cold
surface as silvery black deposit.
James Marsh
Create Marsh test in 1886.
- Highly sensitive
- Detects even trace amounts
- Visible proof
Toxicology
Foundations in 1800s alongside developments in medicine and pathology.
started with Arsenic poisoning.
Karl Landsteiner
- In 1900 founded ABO blood groups
- Won Nobel Prize (1930)
- Serology
Leone Latte
- 1915
- First blood typing test
- Dried blood stain
Edmund Locard (trace evidence)
1877-1966
- “Every contact leaves a trace”
- Significance of physical evidence
- Basis of forensic microscopy
* Founded first crime lab in
Lyon, France 1910
Locard’s Exchange Principle
Wherever he steps, whatever he touches,
whatever he leaves, even unconsciously, will serve
as a silent witness against him.
Not only his fingerprints or his footprints, but his
hair, the fibers from his clothes, the glass he
breaks, the tool mark he leaves, the paint he
scratches, the blood or semen he deposits or
collects.
All of these and more, bear mute witness against
him….
Locard’s Exchange breakdown
This is evidence that does not forget. It is
not confused by the excitement of the
moment. It is not absent because human
witnesses are.
It is factual evidence.
Physical evidence cannot be wrong, it
cannot perjure itself, it cannot be wholly
absent.
Only human failure to find it, study and
understand it, can diminish its value.”
Matheiu Orfila
- “father of forensic toxicology”
- 1814 scientific treatise on
detection of poisons and their
effects on animals
- 1814 scientific treatise on
1840 Marie Lafarge trial
- Marsh Test used
- Landmark case
- 1st use of science in court
conviction
Walter McCrone
- Prominent microscopist
(1916-2002) - Many famous cases
- 1978 Shroud of Turin
Calvin
Goddard
- Pioneer of Ballistics
- Bullet ID via comparison microscope (1920s)
- Bureau of Forensic Ballistics in NYC (1925)
- Helped establish FBI lab (1932)
Sir Alec Jefferys
- 1986 Colin Pitchfork case
- RFLP test
Services of a
crime lab
- Chemical Testing
- Trace Evidence Analysis
- Fingerprinting
- Firearm Identification
- Ballistics
- Serology
- DNA
- Document/Voice Examination
- Toxicology
Crime Scene Analysts
- Crime Scene Investigator
- Crime Scene Technician
- Evidence Technician
Crime Lab Analysts
- Forensic Analyst
- Criminalist
Physical Evidence (CE)
Tangible objects-items that are real, direct and not circumstantial. EX. a weapon used to commit a crime, trace evidence found at a crime scene (blood, hair)
Testimony (CE)
Evidence in the form of witnesses speaking under oath in court. Ex. eyewitnesses, character witnesses
Documentary Evidence (CE)
Any kind of writing, sound, or video. Ex. A transcript of a recorded telephone conversation.
Demonstrative Evidence (CE)
Real evidence used to illustrate, demonstrate, or recreate a prior event. Ex. A card box model of the crime scene.
Pattern (PE)
Pattern Impression when one object comes
into contact with another. Ex. Finger, shoe, tire prints.
Weapons (PE)
Firearm, knife, bludgeon, and
biological. Ex. parts thereof like casings
and cartridges plus marks they
make
Tools (PE)
Hammer, pliers, screwdriver,
electronic scales, baggies. Ex. including marks they make.
Trace (PE)
Minute transfers of materials that
cannot be seen with the unaided eye. Ex.hair, fibers, soil, blood, semen,
paint, chips of plastic or glass
Homicide (Ev relate to crime)
Weapons, bullets, cartridges, and cross-transfer
evidence (fingerprints, shoeprints, tire tracks, blood,
hair, fibers, soil)
Pedestrian hit-and-run (Ev related to crime)
Cross transfer on both the vehicle (blood, tissue, fabric,
hair, fibers) and the pedestrian (paint, plastic, glass, tire
and bumper impressions)
Arson (Ev related to crime)
Ignitable liquids and ignition devices
Burglary (Ev related to crime)
Toolmarks, broken glass, blood, fingerprints, shoeprints,
tire prints
Individual Characteristics
Individual Characteristics
Properties unique to an individual item. Such as fingerprints.
Class Characteristics
Properties common to a group of items. Ex. ABO, caliber, lands, grooves, L or R rifling twist
Databases
Blood Types*
- Fingerprints
- DNA
- Ballistics
- Paint
- Shoeprints
- Tire tracks
Forensic
Databases:
Ballistics
IBIS
Forensic
Databases:
Paint
PDQ
Forensic
Databases:
Shoeprints
& Tire Marks
SICAR
Forensic
Databases:
Fingerprints
IAFIS- National
AFIS- State
4th amendment
unlawful search & seizure
5th amendment
Self-incrimination
14th amendment
due process
Landlords
- Police can enter a property and conduct a search without a warrant if the current tenant gives consent to do so.
- Police can enter a property without permission from the tenant if they have a proper search warrant signed by a judge (landlord is obligated to allow them to enter)
Stages of crime scene processing
- Discovery
- Documentation
- Collection
- Storage
- Transfer
- Analysis
Chain of custody
Evidence collected and stored properly
All people who possessed evidence item
Valid receipts for transfer.
Voir dire
Examination of a witness (qualifications)
or a juror (fair and impartial)
Frye v. U.S. 1923
Established the first standard for admissibility of
scientific evidence.
Dissecting (Stereoscope)
Has
10 -25x magnification considering objective
(usually 3-5x) and ocular (10-15x)
Becke Line
Appears as a
bright halo around outside
of a glass fragment when
the liquid has lower RI than
the glass, whereas the
Becke Line would be on the
inside of the glass when the
liquid has higher RI
