Forensics final exam

whats the Bertillon method and why was it phased out

a method of taking 11 measurements and was phased out because some peoples measurements were identical

henry fauld

Suggested that skin ridge patterns could be important for identification of criminals.

william herschel

English civil servant, who had Indian citizens sign documents with handprints

francis galton

Discussed the anatomy of fingerprints, suggested method of classifying them (loops, arches, and whorls). No two fingerprints are alike and that prints remained unchanged from year to year.

Dr. Juan Vuctiech

Argentinian police officer, developed a workable system capable of filing thousands of prints in a logical and searchable system in 1891

Sir Edward Richard Henry

Developed another classification system adopted by Scotland yard, and is widely used in most English-speaking countries including the United States

what was the will west case of 1990 and how did it impact fingerprints in forensics

Two suspects were brought in with the same bertillion measurements but different fingerprints leading people to use fingerprints as a prefered identification method

what was the ruling in United States v. Byron C. Mitchell?

Fingerprint identification are admissible in court

what are the 3 major principals of fingerprints

1) no two fingerprints are the same

2) fingerprints do not change in an individuals life time

3) fingerprints have general ridge patterns that allow them to be identified

what are the 3 main ridge comparisons

identity, number, shape

epidermis

outermost layer of skin

dermis papille

barrier between epidermis and dermis, determins the ridges on the skin when they are a fetus

dermis

Inner skin

what are the 3 general cases of fingerprints, which is common and rare in the population

Loop 65% whorl 35% arch 5%

how to identify a loop / what are their subclasses

ridges entering \n from one side of the print, recurving, and \n exiting from the same side

Ulnar= the loop opens towards the pinkie

radial = the loop opens toward the index finger

how to identify a whorl / what are their subclasses

All whorls must have at least 2 deltas and a recurve in \n front of each \n Fundamental Principles of Fingerprints

Plain Whorl = imaginary line bwtween deltas

central pocket whorl = no imaginary line btween deltas

double loop = two seperate loop formations

accidental - any pattern that doesn’t fit into the ones listed

how to identify arches / what are their subclasses

no deltas or cores

plain = simple rise or wave

tented = 90 degree or less

what does ACE-V stand for

Analysis, comparison, evaluation, verification

ACE-V (analysis)

look for distorations or surface patterns

ACE-V (Comparison)

Examiner compares print to known print at 3 levels

ACE-V (Evaluate)

Requires one decision of three of the examiner, Identification, Exclusion, and Inconclusive

ACE-V (verification)

Requires and independent examination of the questioned and known prints by a second examiner

Henry FBI identification system

Converts ridge patterns on all 10 fingers into a series of numbers and letters arranged in the form of a fraction

Class characteristics of finger prints

Types of ridge patterns

indivicual characteristics

Position of minutiae, Pores

what is AFIS how does IAFIS work

AFIS uses automatic scanning devices that convert the images the image of a fingerprint

what are the 3 types of prints found at a crime scene

Visible, plastic, latent

visible prints

Prints left by external substance like blood or paint

plastic prints

print imbeded into an object like playdough

latent prints

prints not so visible to the naked eye but shown through oil/ perspiraction left by yhe finger

what is RUVIS

Refelcted ultraviolet imaging system

can located prints in their natural state without chemicals or powders

Fingerprint powders

hard and nonabsortant surfaces, psticks to persiration and oils

Iodine Fuming

poruous surfaces, adheres to perspiraction and fatty oils

ninhindryn

porous and adheres to amino acids in perspiration

super glue and arodox

nonpours surfaces, adheres to perspiration

physical developer

porous surfaces adheres to fatty acids, ailver nitrate reagent

DFO / 1,2indenodine

DFO = porous amino acids and is more sensative to ninhindryun

1\.2indenodine= porous amino acids can replace the 2 step process of ninhyndryn and DFO

how do you preserve fingerprints

take photos and if the item is small enough take the object, but if too large you can use tape to left a copryof the print

how are fingerprints processed on a computer and how is the quality improved

the picture is then converted to a digital file and then can be inproved in quality with the number of pixels, contrast to the background, qnd overall brgihtness

define fire arms

define ballistics

what are the 3 major types of hand guns

difference between single action and double action revolverr

characteristics of a single shot pistol

what are the 3 major types of revolvers / whats their differences

what are the characteristics of the semi automatic pistol

what are the two types of long gun / what are their differences

what is rifling and why is it done

what are the 3 types of rifling methods

what are the compnenets of amunition

what are the class characterisics of a bullet

what are the individual characterstics of the bullet

What are the past and current automated firearm searches? 

What is gun shot residue? What is primer residue? 

what are the 2 tests to run for GSR / what do they test for / what do positive and negative tests look like

what is a SEM spectrum and what is it used for

how does serial number restoration work and what are the chemicals

how are fire arms and amunition processed in a crime scene

what are the steps for calculating the height of the shooter given distance and angle of impact

what are the class and individual characteristics of tool marks

how are shoe impressions preserved at a crime scene

what is electrostatic lifting and how does it work

describe how to cast things chemically in two ways

describe the casting process normally and in snow

class and individual characteristics of a tire

what is sicar

whats the difference between a chemical and physical property

chemical = describes a substance in reletion to another substance

physical = describes a substance withput mentioning another substance

matter

anythong that has mass and ocupies space

element

simpliest sibstance, building blocks from which all matter is composed

atom

smallest particle in an element, protons, elextrons, nuetrons

compoud

pure substance composed of two or more elements

molecule

smallest unit of a compound

what are the 3 states of matter / what makes them unique

solid = has definite shape

liquid = occupies specific space

gas = no definite shape or space but will fill a container

what are the 3 phase changes

Metric conversions

kilo -> hecta →daka → basic unit → decit→ centi → mili

whats an intensive property

a property that is not dependent of on the size of the object

density calculation / what factors effect density

what is refraction and whats the refraction index

what are the two types of solids

what unique property do crystalline solids have

what is dispersion

true or false, light behaves like a wave AND a particle

true

what is frequency and wavelength / whats their reletionship

red vs violet wavelength, frequency, energy

radio waves vs gamma waves wavelength, frequency, energy

what is coherent and incoherent radiation

what are the 4 main types of glass and their properties

what are the class and individual characteristics of glass

3 ways to calculate density of glass

how to use snells law to calculate refractive index of a liquidi

How is the refractive index of a glass sample determined

what are becke lines

what are the two types of glass fractures

Know the unique properties to each of fracture type

What can be learned by studying glass fracture patterns?

which side the hole is wider on in a glass fracture

how chonchoidal Striations or wallner lines are used to determine directionality on  radial and concentric edge of glass.

 how velocity correlates to the shape of the hole in the class and to type of weapon

Given a fracture pattern, be able to determine the sequence of events

Know how to collect glass fragments