Exam #2 Flashcards
The pores of the sweat glands are located in the:
skin ridges
Prints that are not readily visible are commonly referred to as:
latent
To permanently alter the fingerprint and produce scars, one must damage the:
dermal papillae
The most common ridge pattern is the:
loop
The number of deltas found in an arch pattern is ________ the number of deltas found in a loop pattern.
less than
In the Primary Classification System, a finger is assigned numerical value if its pattern is a:
whorl
The fingerprint classification system used in most English speaking countries was devised by:
Henry
What did Henry do?
devised the fingerprint classification system that is used in most english speaking countries
What is AFIS
computerized fingerprint database
Prints impressed in a bar of soap are referred to as:
plastic
Will West was the man who:
had a virtual “double” with a similar name
Physical developer contains:
silver nitrate
Superglue fuming is NOT suitable for use on:
cardboard
Currently, which of the following, in conjunction with chemically induced fluorescence, is most often used to visualize latent prints?
Laser illumination
IR light
UV light
High-intensity light sources
high-intensity light sources
Dusting to visualize a latent print on finished leather and rough plastic is best done with a:
magna (magnetic) brush
After successfully visualizing a latent print on an object, an investigator should next:
take a 1:1 photograph of the print
Which of the following types of fingerprints are more likely to be found impressed in soft wax?
Hidden
Visible
Plastic
Latent
plastic
Under which circumstances have two people been found to have identical fingerprints?
Siamese twins
Fraternal twins
Identical twins
None to date
none to date
Protein residues are best developed into fingerprint impressions with:
ninhydrin
Which statement is true of a partial fingerprint?
-It must show at least a little of all ten fingers.
- Any print is sufficient for identification as long as there is enough to identify its basic pattern.
- At least 75% of the pattern must be present for identification.
- Any print can identify a criminal if it shows an adequate number of ridge characteristics.
any print can identify a criminal if it shows an adequate number of ridge characteristics
Which of the following is NOT a ridge characteristic of a fingerprint?
Island
Core
Enclosure
Bifurcation
core
A point-by-point comparison of a fingerprint’s ________ must be demonstrated in order to prove identity.
minutiae
Which step of the ACE-V process requires the examiner to identify any distortions associated with the friction ridges?
Analysis
Evaluation
Verification
Comparison
analysis
Fingerprints are formed:
during fetal development
The friction skin ridges:
Have no useful purpose other than identification.
Provide a firmer grip.
Resist slippage.
Both B and C
both b and c
The FBI has an internal unit called FACE. What does FACE stand for?
Facial Analysis, Comparison, and Evaluation
Which of the following pathways would represent an accurate portrayal depicting the collections steps in gathering biometric data?
-Biometric sensor Pre-processing Feature Extractor Template generator
-Stored templates Matcher Template generator Decision
-Decision Template generator Pre-processing Stored templates
-Biometric sensor Feature extractor Matcher Decision
Biometric sensor Pre-processing Feature Extractor Template generator
What is one of the new features that has been implemented with the NGI?
Sex offender registry status
Voice recognition
New Tenprint system
Gang affiliation
new tenprint system
What function of biometrics would law enforcement be implementing if they wanted to look for a person of interest accused of sexual assault in a large crowd at a sports stadium?
biometric matching or verification
Which scanners are largely outdated and considered to be too intrusive to be practical in real-world applications?
retina
Which of the following would not be considered a physiological biometric?
Voice
Fingerprints
Iris
Hand
voice
Which module is responsible for finding patterns in the traits extracted by the sensor using mathematical equations?
feature extraction
Which of the following technologies is replacing retina biometrics because it is an all-around better technology, which is functional for both law enforcement and business security.
Iris biometrics
Cornea biometrics
Sclera biometrics
Pupil biometrics
iris biometrics
Out of the various forms of behavioral biometrics, which of the following is the least accurate?
Handwriting
Voice recognition
Gait recognition
Keyboard dynamics
gait recognition
Which of the following systems is highly beneficial for law enforcement safety in that it allows for officers to fingerprint individuals they come into contact with quickly to detect whether or not they pose a potential threat?
RISC
NPPS
IPS
MorphoTrak
RISC
Which process captures a person’s biometric data and stores it in a database for later use?
enrollment process
What is the primary disadvantage with Principal Component Analysis?
a full frontal face image is needed to be a viable sample
Which of the following is not considered a behavioral biometric?
Facial scan
Gait Recognition
Keystroke patterns
Handwriting
facial scan
Which of the following features would not serve as a variable for analysis in biometric facial recognition?
Chin
Neck
Widow’s peak
Cheekbones
neck
What does the FBI’s acronym NPPS stand for?
national palm print system
Which of the following is not expected to show any evidential marks or impressions?
A fired bullet
A shotgun pellet
A cartridge casing fired from a handgun
A cartridge casing fired from a shotgun
a shotgun pellet
Tools and tool marks are often found at burglary scenes and can be useful evidence. Proper evidence collection by the field investigator would include:
taking a photograph and cast of the marks if necessary
The reason grooves are rifled into the bore of a gun is so that a:
bullet will be made to spin and have a true and accurate course on leaving the barrel
Distinctive markings of shells and cartridges can be made by what 3 things?
Firing pin
Extractor and ejector mechanism
Breech face mark
Which of the following factors is least likely to be considered by the examining tool mark technician?
The brand name of the tool
The angle at which the tool was held
The side or portion of the tool making the impression
The direction of the tool movement as it passes over the surface
the brand name of the tool
Which is NOT a class characteristic of a suspect’s sneaker?
Wear marks
Color
Size
Brand
wear marks
The likelihood of detecting GSR on swabs taken from living subjects more than six hours after a firing has occurred is ________ the likelihood of detecting GSR within two hours of a firing.
less than
Objects bearing tool marks should either be submitted intact to the crime lab or a ________ should be taken of the tool mark.
cast
Dust imprints found at a crime scene can be lifted using:
an electrostatic lifting device
The barrel of a shotgun:
Is generally shorter than that of a rifle.
Is wider at the end to concentrate shot.
Is indistinguishable from that of a rifle.
Is smooth without the grooves and lands found in rifles.
is smooth without the grooves and lands found in rifles
Generally, the gauge of a shotgun is ________ to the diameter of its barrel.
directly related
Which of the following results is not possible from a laboratory examination of firearm evidence?
-Restoring serial numbers ground off the gun
-Identifying a bullet as having been combined with a particular shell prior to being discharged
-Determining that two or more cartridge cases were fired from the same weapon
-Determining how far from the victim the weapon was held
identifying a bullet as having been combined with a particular shell prior to being discharged
Two-dimensional imprints found at a crime scene can be lifted using:
an electrostatic lifting device
Who makes the final determination about whether or not two bullets were fired by the same gun?
a trained firearms examiner
Which of the following procedures is not to be followed in collecting and packaging firearms evidence at the crime scene?
Marking an empty cartridge case on its base for identification
Marking a fired bullet on its base for identification
Avoiding inserting a stick or pencil into the barrel of a weapon
Unloading a weapon before shipping it to the crime laboratory
marking an empty cartridge case on its base for identification
Discharged evidence bullets must be carefully handled to avoid damage to the:
striation markings
When an etching agent is applied to a metal surface in order to restore a removed serial number the stamped area will dissolve at ________ as the unstamped area.
a greater rate
Generally speaking, the amount of gun powder particles found around a bullet hole is ________ to the distance from which the weapon was fired.
directly related
A wear pattern, cut, gouge, or other damage pattern can impart ________ characteristics to a shoe.
Indivuidal
The presence of gunpowder residues on a garment whose color conceals the existence of the residue is best revealed by:
infrared photography
Which is a true statement about the fracturing of glass?
-Radial cracks form afterward, starting on the same side as the destructive force.
-Concentric fractures form first, on the same side as the destructive force.
-Concentric fractures form first, starting on the side opposite the destructive force.
-Radial cracks appear first, starting on the side opposite the destructive force.
radial cracks appear first, starting on the side opposite the destructive force
To explain the events that occur after radiation is absorbed by a substance, light must be characterized as:
a stream of discrete particles
The fracture pattern of glass usually has:
Concentric lines.
Radial and concentric lines.
Directional lines.
Radial lines.
radial and concentric lines
Crystalline solids, with the exception of ________ crystals, exhibit ________, or the property of refracting a beam of light into two different ray components.
Amorphous, refraction
Calcite, refractive index
Cubic, double refraction
Glass, optical properties
cubic, double refraction
The process of a glass prism separating sunlight into component colors is called:
dispersion
The refractive index of a substance varies with:
Its temperature.
All of the above
The wavelength of the light passing through it.
The color of the light passing through it.
all of the above
The two most important physical properties of glass for forensic comparisons are:
refractive index and density
If glass cannot be physically pieced together then the control and question glass are best compared as to their:
refractive index and density
Sublimation is defined as a change of state from:
solid to gas
The photons of which source have the LEAST amount of energy?
Microwaves
Gamma rays
Infrared rays
Radio waves
radio waves
A hot-stage microscope or the GRIM 3 is used to determine the ________ of glass fragments.
refractive index
________ is the visual effect caused by an object’s absorption of certain portions of the visible light spectrum and transmission or reflection of others.
color
The smallest particle of an element that can exist and still retain its identity as that element is the:
atom
When a bullet penetrates a panel of glass, it leaves a crater-shaped hole that:
is wider on the exit side
A piece of glass is immersed in a liquid. It proceeds to float on the liquid’s surface. This shows that the density of the glass is ________ the density of the liquid.
less than
Which physical state has volume but no specific shape?
liquid
A(n) ________ property describes the behavior of a substance without reference to any other substance while a(n) ________ property describes the behavior of a substance when it reacts or combines with another substance.
physical; chemical
Flotation is a method used by scientists to determine the ________ of a particle of glass.
desnity
What three things can a fingerprint be classified as?
loops
whorls
arches
What supreme court case challenged that fingerprints could not be proved unique under the criteria in the doubert case?
1999 US vs Mitchell
What are fingerprints?
a reproduction of friction skin ridges
What are minutiae?
ridge characteristics used to classify and match prints
it is the identity, number, and location of these that make a fingerprint indivuidal
A fingerprint pattern stems from what layer of the skin?
papilae
What is the most popular type of finger print pattern?
loop
What is a unlar loop?
opens towards the little finger
What is a radial loop?
opens towards the thumb
All loops must have at least one what?
delta
a triangle looking pattern
Whorls are divided into 4 groups caled:
plain
central pocket loop
double loop
accidental/mixed
What do arches not have any of?
deltas
What must a whrol have two of?
deltas
What are the two categories arches are split into?
plain arches
tented arches
What are the 4 steps in identifying and individualizing a fingerprint?
analysis
comparison
evaluation
verification
What are the two biometric traits?
biological
behavioral
What are two examples of biological traits?
finger prints and retinal scans
What are two examples of behavioral traits?
handwriting and brainwaves
What is total maginfication?
ocular magnification x objective magnification
What does biofringent mean and what is an example of it?
split beams of light
fibers
What is forensic palynology?
the collection and examination of pollen and spores connected with crime scenes, illegal activities, or terrorism
What is the primary tool used in forensic palynology?
the mircoscope
The raised areas of a gun barrel are known as ______ and the depressed areas are known as ______?
lands; groves
this is reversed when looking at a bullet REMEMBER THIS
What is caliber?
the diameter of the gun barrel measured between opposite lands
What are three ways to determine the class characteristics of a gun?
lands/groves (number and size)
twist
caliber
What are striation marks?
lines formed on the inside of the barrel that translate on the bullet
provide indivuidal characteristics
What is the primer cup?
the back of the bullet
What is a bullet wipe?
the dark ring of GSR around the bullet hole
What are properties and what are the type types?
the identifying characteristics of substances
chemical and physical
What are examples of physical properties?
weight
size
color
What is a chemical property?
the behavior of a substance when it reacts/combines with another substance
What is often used instead of weight when comparing substances?
mass
_____ is affected by gravity, ______ is not!
weight; mass
What is a density?
an intensive property of matter
What does it mean to be an intensive property?
the density remains the same regardless of the sample size
What is refraction?
the bending of light waves because of a change in velocity
What is refractive index?
the way light is bent
the ratio of the velocity of light in a vacuum to that in a medium under examination
What is birefrigence?
taking the difference between the refractive indexes
What is it called when the becke line disappears?
match point
How do you know when you have reached a match point?
when the becke line disappears
What is the difference between latent and patent print?
latent: requires extra work to see
patent: you can already see
What is anthropometry?
the first system of ID using bodily meausrements
created by bertillonage
What does iodine fuming do/used for?
revealing fingerprints while still allowing you to see the content under it
used for things like suicide notes
What are dermal papillae and how are they important in fingerprinting?
the layer of skin between the epidermis and dermis
ridges in the skin that create the individual characteristics in a fingerprint
Describe the difference between an arch and a tented arch.
a tented arch is taller and narrower than a regular arch
Describe the difference between a pocket loop and a whorl.
a pocket loop is smaller and has a narrow tail
a whorl is wider (has more swirls) and has a wider tail
What is the ACE-V method of matching prints? Describe/ explain each step.
A- Analysis (clarity of an image, look for possible distortions)
C- Comparison (compare questioned print on different levels)
E- Evaluate (identification, exclusion, inconclusive)
V- Verification (examiners conclusion checked against someone else’s)
On what levels can fingerprints be compared? Explain and give examples.
3 levels
1- ridge patters
2- brifercations/minutiae
3- pores, skars, permanent minutiae
What are three ways that we can prevent inaccurately matching fingerprints?
- run it through NIBIN
- double check it using ACE-V
- make sure you have a good print and a complete match
List and describe the three types of fingerprints that may be found at a crime scene.
patent - visible without processing
plastic - impressions on soft materials
latent - requires processing to become visible
List two types of specialized fingerprint powders and name one advantage each has over traditional fingerprint powder.
fluorescent powder - bright under uv light and provides more contrast
small particle reagent (SPR) - a spray that is good for prints that are wet and are on moist, non porous surfaces
What is the most commonly used chemical method to visualize latent fingerprints on porous materials? If this method is unsuccessful, what other technique typically is used?
ninhydrin
superglue fuming; iodine fuming
What is digital imaging and how is it used in fingerprint analysis? What is the greatest limitation to digital imaging?
it can compare latent prints and enhance prints for easier comparison
If you have an object that is wet, what methods could you use to develop the print? Why does this work?
small particle reagent (SPR)
it attaches to lipids and shows washed up or wet prints
Be sure you can pick out the best method for developing prints in certain situations, such as a porous piece of paper, textured surface, etc.
porous - chemical
textured - physical
What are the two main functions of biometrics? Be sure you can explain them.
1) matching and verification - ability to identify a criminal by using biometric characteristics
2) identification
What are the two primary types of forensic biometrics? Be sure you can give examples of methods that fall into each category.
physiological biometrics - fingerprints, iris, retinal, and facial scans
behavioral biometrics - handwriting, voice, keystroke, gait recognition
What is the first process that each biometric system must perform? What does it consist of?
verification and voluntary enrollment in the system
can ID someone using biometric characteristics
What biometric system process or module performs most of the “heavy lifting” for the system?
feature extractor
finds patterns in the traits extracted by biometric sensors
Which module is responsible for saving all the raw data produced by feature extraction and putting it into a simple and easy to read format for the system?
template generation - placed data in an easy to read format like a database
What are some of the reasons why iris biometrics is replacing retina biometrics?
less invasive; more accurate; more individualized and permanent
What is one significant advantage of automated facial recognition, as compared to other forms of biometrics such as iris and fingerprint systems?
it is non-invasive and does not require voluntary enrollment
What is the difference between a real image and a virtual image?
real image - viewed directly
virtual image - magnified image seen through a lens
Why does a compound microscope produce greater magnification than a magnifying glass? How does the eyepiece lens contribute to magnification?
it multiplies the magnification of the objective lens
can increase and decrease the magnification power
What is vertical illumination and under what conditions would a forensic scientist use it to examine a sample? Why is it superior to transmitted illumination under such conditions?
used for opaque items
uses a stereoscope
when light comes from above and reflects off an object
Why might an examiner choose a microscope with a lesser magnification to study a specimen?
want to see the whole specimen; larger field of view
less detailed objects need to be viewed
When might you use a polarizing scope?
if the object scatters light (like crystals, soil, small minerals)
When might you use a microspectrophotometer?
looks at how the object absorbs light (like counterfeit money, paint, and fibers)
When might you use a scanning electron microscope?
use on a micro level to create an HD image with depth (like gun shot residue (GSR))
How can a scanning electron microscope be used to determine whether a suspect has recently fired a gun?
reveals gun shot residue
What is distance determination?
how far the shot was fired
What is luminol?
a substance to look at impressions in blood
What is a SEM stub?
a device used to catch molecules of gun shot residue
What is rifling?
the spiral grooves cut in the gun causing the bullet to spin
List some examples of class characteristics of a gun barrel.
lands
grooves
twist
Describe how a firearms examiner compares two bullets. What characteristic does an examiner most often use to identify bullets and why?
striation marks
lands and grooves
twist
firing pin impressions
breech face matches
List two reasons why striations on bullets fired from the same gun may vary slightly.
grit and rust inside the barrel
general wear and tear on the gun
Besides the barrel, what parts of a firearm may leave distinctive markings on a shell cartridge?
ejector
extractor
firing pin
breech face
List three characteristics of a bullet hole that indicate that the shot was fired at extremely close range.
GSR present
stellate star present
concentrated GSR pattern around the bullet entrance (dark rim)
What evidence do investigators look for when trying to determine whether a suspect has fired a handgun? Where is such evidence typically found and why?
GSR present on the hands/clothing
Describe how a criminalist restores an obliterated serial number on a weapon. Why is this an important forensic technique?
the metal there is already weakened so smooth the damaged area and apply an acid based solution which will reveal the numbers
Name two types of marks that impart individuality to a tool and explain how the marks are made.
marks from the creation of the tool
marks from usage of the tool
How would a forensic odontologist be able to determine that teeth were from a young child?
number of teeth
size of the mouth - shorter arch when younger
Why is the metric system of measurement easier to use than the “English system”? Which system is used in the United States?
metric system is more standardized
americans use the imperial system
Define the terms physical property and chemical property. Be sure you can give examples of each one.
physical - color, weight, volume, melting point
chemical - behavior of a substance, reactions, color test for drugs
How does heat affect the density of gases and liquids?
as they are heated, the become less dense
Define the terms refraction and refractive index.
refraction - bending the light - change way to see
refractive index - used when comparing things - measures refraction
Define intensive property and name two intensive properties of matter.
something that doesn’t change density no matter how big the sample size is
color and temperature are two examples
What is color? What determines the color of an opaque object?
color - how we see things in visible light
what wave lengths are being absorbed
List two factors that make it difficult for criminalists to compare glass samples.
shatters too small
could be tampered with
too similar
Describe the process of flotation and explain what it is used for.
puts objects in liquids with different densities and when it floats thats the density of the object (same as liquid)
used to determine density
What is the Becke line and how is it used to determine the refractive index of a glass sample?
line around the pieces of glass when their refractive index doesnt match
when this disappears, that means there is a match point
How can an investigator determine the order in which several successive penetrations of a glass occurred?
cracks - when one line stops at another
