analytical skills
the ability to identify a concept or problem, to isolate its component parts, to organize information for decision making, to establish criteria for evaluation, and to draw appropriate conclusions
deductive reasoning
deriving a conclusion from the facts using a series of logical steps
eyewitnesses
a person who has seen someone or something related to a crime and can communicate his or her obervations
fact
a statement or information that can be verified
forensic
relating to the application of scientific knowledge to legal questions
logical
reasoned from facts
observations
what a person perceives using her or her senses
opinion
personal belief founded on judgement rather than on direct experience or knowledge
perception
information received from the senses
Eye Witness
can be faulty, but in some cases can be precise.
Innocence Project
Found that up to 87% of wrongful convictions cases resulted from flawed eyewitness testimony.
chain of custody
the documented and unbroken transfer of evidence
circumstantial evidence
(indirect evidence) evidence used to imply a act but does not support it directly
class evidence
material that connects an individual or thing to a certain group
crime-scene investigation
a multidisciplinary approach in which scientific and legal professional work together to solve a crime
crime-scene reconstruction
a hypothesis of the sequence of events from before the crime was committed through its commission
datum point
a permanent, fixed point of reference used in mapping a crime scene
direct evidence
evidence that (if authentic) supports an alleged fact of a case
first responder
the first safety official to arrive at a crime scene
individual evidence
a kind of evidence that identifies a particular person or thing
paper bindle
a folded paper used to hold trace evidence
primary crime scene
the location where the crime took place
secondary crime scene
a location other than the primary scene, but that is related to the crime; where evidence is found
trace evidence
small but measurable amounts of physical or biological material found at a crime scene
triangulation
a mathematical method of estimating positions of objects at a location such as a crime scene, given locations of stationary objects
Locard's Principle of Exchange
contacts between people and objects during a crime can result in a transfer of material
First Responder
Must identify the extent of a crime scene, including primary and secondary scenes when possible, secure the scene(s), an segregate witnesses
Comparison microscope
a compound microscope that allows side-by-side comparison of samples, such as hair or fibers
cortex
the region of a hair located outside the medulla that contains granules of pigment
cuticle
the tough outer covering of a hair that is composed of overlapping layers
gas chromatography
a method of separating chemicals to establish their quantities
hair follicle
the actively growing base of a hair that contains DNA and living cells
hair shaft
part of the hair above the follicle; contains mitochondrial DNA
keratin
a type of fibrous protein that makes up the majority of the cortex of a hair
medulla
the central core of a hair
melanin granules
bits of pigment found in the cortex of the hair
mitochondrial DNA (mtDNA)
genetic material in the mitochondria of the cytoplasm of a cell; only inherited from the mother
nuclear DNA
genetic material in the nucleus of a cell
19th century
century hair analysis was first used as evidence
amorphous
without a defined shape; fibers composed of a loose arrangement of polymers that are soft, elastic, and absorbing (for example, cotton)
crystalline
geometrically shaped; fibers composed of polymers packed side by side,which makes them stiff and strong (for example, flax)
direct transfer
the passing of evidence, such as a fiber, from victim to suspect or vice versa
fiber
the smallest indivisible unit of a textile, it must be at least 100 times longer than wide
mineral fiber
a collection of mineral crystals formed into a recognizable pattern
monomer
small, repeating molecules that can link to form polymers
natural fiber
a fiber produced and harvested from animal, plant, or mineral sources
polymer
a substance composed of long chains of repeating molecules (monomers)
secondary transfer
the transfer of evidence such as a fiber from a source (for example, a carpet) to a person (suspect), and then to another person (victim)
synthetic fiber
a fiber made from a manufactured substance such as plastic
textile
a flexible, flat material made by interlacing yarns (or "threads")
warp
a lengthwise yarn or thread in a weave
weft
a crosswise yarn or thread in a weave
yarn
fibers that have been spun together
arch
a fingerprint pattern in which the ridge pattern originates from one side of the print and continues to the other side
core
a center of a loop
delta
a triangular ridge pattern
IAFIS
FBI-developed national data-base of more than 76 million criminal fingerprints and criminal histories
latent fingerprint
a concealed fingerprint made visible through use of powders or forensic techniques
loop
a fingerprint pattern in which the ridge pattern flows inward and returns in the direction of the origin
minutiae
the combination of details in the shapes and positions of ridges in fingerprints that makes each unique; also called ridge characteristics
patent fingerprint
a visible fingerprint produced when fingers coated with blood, ink, or some other substance touch a surface and transfer their print to that surface
ridge count
the number of ridges between the center of a delta and the core of a loop
ridge pattern
the recognizable pattern of the ridges found in the end pads of fingers that form lines on the surfaces of objects in a fingerprint. They fall into three categories: arches, loops, and whorls
ten card
a form used to record and preserve a person's fingerprint
whorl
a fingerprint pattern that resembles a bulls-eye
Juan Vucetich
Who solved the first murder by using fingerprints?
types of minutiae
ridge ending, fork, island ridge, dot, bridge, spur, eye, double bifurcation, delta, trifurcation
counterfeiting
typically, the forging of currency; also the forging of government-issued documents (postage stamps) and production of fake brand-name products for profit
currency
a printed document issued by a bank , guaranteeing payment to the holder on demand
document analysis
the examination of questioned documents with known material using a variety of criteria such as authenticity, alterations, erasures, and obliterations
document expert
a person who scientifically analyzes handwritten, typewritten, photo-copied, and computer-generated documents and their materials for authenticity
exemplar
a standard document of known origin and authorship used in handwriting analysis for comparison to documents of unknown authorship (questioned documents)
forgery
the making, altering, or falsifying of personal documents or other objects with the intention of deception
fraudulence
(fraud) deliberate deception practiced to secure unfair or illegal financial gain
questioned document
any signature, hand-writing, typewriting, or other written mark whose source or authenticity is in dispute or uncertain
ballistics
the study of a projectile in flight; includes the launch and behavior of the projectile
breech
the end of the barrel attached to the firing mechanism of a firearm where the cartridge is loaded and unloaded
bullet
the projectile that is fired when a firearm is discharged
caliber
the inside diameter of a firearm
cartridge
a case that holds a bullet, primer powder, and gunpowder
firearm
a portable gun that uses a confined propellant to expel a projectile out of a barrel
gunshot residue
soot and particles of unburned gunpowder deposited on a person who discharges a firearm; may also be found on close-range victims and adjacent surfaces
rifling
the ridges (lands) and depressions (grooves) found on the inside of the firearm's barrel that are created when the firearm is manufactured
pistol
a handgun with a barrel and chamber that are connected
revolver
a handgun with a barrel and chamber that are connected
rifle
a long gun that has a barrel with spiral grooves and that is fired from shoulder level
rifling
the spiral pattern on a fired projectile made by the lands and grooves in the barrel of a firearm
trajectory
the flight path of a projectile