Answers
Forensic
Science Final Review
Packet#1
1.What
is Forensic Science?
A.
Forensics- is the direct application of scientific knowledge and techniques to
matters of law.
2.What is Locard Exchange Principle ??
“…that any two surfaces coming in contact leave trace evidence behind. ”Dr.
Edmond Locard,
French investigator, believed there was cross-transference of small traces
between a perpetrator and a victim Locard theorized that whenever two surfaces
come into contact, a transfer of minutiae, however slight, would occur. or the
crime scene.
3. Who
created the first crime lab in Lyons, France in 1910,
the
first crime lab was created by Edmond Locard.
4. a.
What is evidence ?Anything
that has been used, left, removed, altered, or contaminated during the
commission of a crime is considered evidence.
b.
What is trace evidence?
Taken
from its name, trace evidence is considered to be any minutiae that can
be found. This includes fingerprints, hairs, fibers, and various fluids (blood,
semen).
5.
Describe the trace evidence associated with convicted Atlanta Child Serial
Killer, Wayne Williams.
•
The Atlanta child killer
•
25+ victims
6. What
is it called when no body (without a body) is found associated with the crime
scene?
Corpus Delicti:
(without a body) no body, or missing murder victim.
On the Eve of
Thanksgiving, Helle Crafts disappeared from her home in Connecticut.
7. What
is Evidence?
Anything that
has been used, left, removed, altered, or contaminated during the commission of
a crime.
8.What is
impression evidence?
When shoe,
footprints or tire prints are found at a crime scene, all attempts are made to
preserve the impressions or reproductions are created.
9.
Describe 2 differences between impressions and prints?
(1.).)prints
are 2D and made by placing material on, transferring from or by removing it from
a hard surface. But an impression is 3-D and usually created on pliable
materials such as soils.
(2.)
usually
prints are lifted from a surface, impressions are preserved with a cast.
10. What technique is used
to preserve a print in dirt or dust?
if the print
is made of dust or dirt, the print is lifted by applying a lifting material(it
is dusted and lifted with an adhesive)If the print is difficult to lift and
electrostatic charge is applied , especially with sand prints.
11. How
does the Kastle-Meyer Test identify Blood Evidence?
peroxidase-like
reaction an enzyme reaction with peroxide and color reaction with
phenolphthalein.
horseradish
12.
Describe the Luminol Test for the presence of blood:.?
Instead a color reaction: it is a reaction to create LIGHT called Luminescences.
13. What
is a blood drop spatter pattern?
Blood drop’s
behavior in the air once it has left the body. Once the drop of blood
impacts a surface, the spatter pattern or the blood stain is created.
14. The size and shape of the blood drop patterns depends
( 1.)the
amount of blood
. (2.)
the distance it is dropped
(3.)
the angle it was dropped.
15. A
blow back pattern is created in what way?
(2.) depends
on the angle at which it impacts
The general rule is that the greater the angle, the more elliptical the
shape.
16.
Finally, the shape of the blood drop patterns depends on distance blood
dropped-
The general rule is that the greater the distance the
larger
the
spatter diameter.
17.
ESSAY:
Using
Newton’s Laws of Motion, how is the amount of force related to the velocity of
the blood drop?
If more
force is involved there will be an acceleration on the same droplet
of blood a.)
When does low velocity become medium velocity blood spatter?
Low becomes to
medium velocity>25 m/s
b.)
When does medium velocity changes to high velocity?
medium velocity changes to high velocity>100 m/s
18. In
the study of Blood Spatter Patterns (BSP), what is a
Void
Pattern?
It is
an empty space where blood should have been.
19. How
is a cast off blood spatter pattern created?
Castoff is
Created by the movement of a bloody object to throw off the blood.
20. ESSAY
a.
What are blood
trails?
dripping
pattern, the blood had dripped from a bloody source onto a surface and the
trails from a body being dragged or carried
b.
The pattern of Blood trails , depend on what 2 things?
1.) how
fast the person was moving or dragged
2.) the
volume of blood they are casting off
c.
What is Directionality? -
blood stains
will have “tails” with the drop. The tail points in the direction in which the
drop was moving.
d.
What does it mean about the movement of a victim if the
path
of the
blood drops
is several feet apart with tails?
indicates
someone was bleeding and also running.
21. What
are the 2 types of transfer blood pattern stains and how are they created? (1.)
smears
– left by movement of a bleeding persons-hair transfer- hair movement
(2.) (swipe) with
blood creates a unique pattern.
22. Blood
patterns from a major artery are called an
arterial spurt.
.
23. How
are these spurts created?
When injury to
the neck is involved, the carotid artery may be severed and the heart pumps the
blood out in spurts.
24. What
2 factors determine the shape and size of pooled blood?
(1.)
Amount of blood pooled near a bloody object or from the victim.
(2.)
time it takes for the blood to coagulate- solid and liquid parts separate
25. What
is the difference between somatic and cellular death? a.)
Somatic
death
-
when
the individual is irreversibly unconscious and unaware of himself and the world.
b).Cellular death
-when
the cells quit respiration and metabolism. When all cells are dead, the body is
dead.
26. What
is meant by the Postmortem interval ?
determining
time passed after death
27. What is algor mortis ?
cooling of the
body-After death the body stops breathing, without O2 the body
cannot maintain 98.6 oF
28. What
is cooling rate of a body??
1 degree per hour until body reaches ambient temperatures (surroundings)
30. What is Livor Mortis, also called lividity?
Discoloration when the red blood cells separate and settle to the lowest point
of gravity.
31. What
can you conclude about the placement of a corpse, if lividity appears on the
front but the corpse in on it’s back ?
the corpse was
moved Postmortem
.
32. a.)
What factors may cause unusual the lividity pattern on if the body??
If the body is lying on an object. Ex. or bedding
b.)
Evidence of tampering with the position of a body after death can be obtained by
evaluating the
livor mortis.
.
33. What
is Rigor Mortis ? –
within 15
minutes of death (up to 36 hours) the body stiffens due to the accumulation of
chemical waste products in the muscles.
34.
Describe the appearance of Initial Decay -The
corpse appears fresh externally but is decomposing internally due
to the activities of bacteria present before death.
35. What is another name for putrefaction?
what is it’s
appearance? (Bloating)-The corpse is swollen by gases, with the odor of decaying
flesh.Begins with a green flush over the abdomen+ bloating spreads to trunk,
limbs, then face
36. Where
is ground
zero in the putrefaction process?
the cecum,
a pouch at the head of the large intestines. the cecum is full of
bacteria that assist in digestion, they are policed by the white blood cells or
leukocytes. With death, the bacteria break through the intestine
wall, use the circulatory system to travel
37.
During black putrefaction pressure builds and eventually, fluids are released
from the body. What is this process called?
these gases
inflate the body until the pressure is so great = fluids are purged
from the body.
38. In
putrefaction, the smell is at it’s worst. What are the names of the 2 sulfur
based gases that are responsible for the odors? = sulfur gases named putresine
and
cadaverine
39.
ESSAY : What is the purpose the “Body Farm” at the University of Tennessee,
Department of Anthropology? How do they assist with death scene investigations?
is to
study human decomposition in various physical environments.
40 a.)
How is Forensic Entomology used to determine Time of Death?
Time of Death can be determined using insect evidence gathered
from and around a corpse because the life cycle of insects are like clocks,
identifying the variety of species and stages in their life cycle can be
used to determine time of death. Additionally the insects species on the
corpse
can be used to determine if the corpse was moved postmortem.
b.)
According
to forensic entomologists, which "witness" is the first to arrive at a death
scene??
In certain cases of suspicious death, the length of time that insects have
colonized remains is useful to police investigations in helping to determine
time
c.)
Modeling: draw the life cycle of the Blow Fly in the space below:
Packet #2
41. For
what 2 reasons is an examination of physical evidence considered in an
investigations ? (1.)it
is done for identification and
(2.)comparison
42. What are exemplars and how are they used?
a standard and
/or reference specimen, sometimes collect at the crime scene . To subject both
to the samples to analysis and test and to determine if they have the same or
similar origins
43. Who
is a Forensic Odontologist?
a dentist who specializes in the comparison and identification of dental
evidence from impressions or from actual teeth in/from a skull
44.
ESSAY
a. In
criminal investigation , describe 2 ways in which dental evidence or “bite
marks” can be helpful?
To
establish the age and identity of a homicide victim and to associate a
suspect with a crime scene using bite-mark analysis( compare).
b.
Explain why individuals can be identified by their teeth, sometimes over using a
fingerprint?
because
everyone’s teeth are different. Since almost everyone has been to a dentist at
one time, most of us have a dental record. Teeth are a better identifier than
fingerprints, Not everyone has been fingerprinted!
45.
What is Density
?
is a intensive
physical property of matter. Density = mass/ volume, It is unique to a substance.often
used to compare and identify glass evidence
46. Why
is it possible to place a suspect at a crime scene if they have a small piece of
glass on their clothing ?
because Glass
from various sources all have slightly different densities
47.
ESSAY
What
are class characteristics and how do they differ from individual characteristics
? Give an example of each.
properties of evidence that can only be associated with a group and never with a
single source Example =glass. properties of evidence that can be associated with with a
single source because of unique characteristics observed in the evidence Example
=the sole of a used shoe will pickup uniqueness as it is worn over time..
48. Where
is
tempered
glass
or safety glass used in autos?
is made strong
by rapid heating-and –cooling process that introduces stress to the glass it is
used in side and back windows in autos.
49.
Why is tempered glass used in autos?
tempered glass breaks ®
it breaks into tiny cubes with no sharp edges. tempered glass is used in the
side and back windows of the car.
50.
According to geologist, what is soil?
define soil
as the organic (carbon-containing) and mineral (rock) matter composing the
Earth.
51. When
a forensic geologist is investigating a crime scene, what materials are
considered soil evidence?
all natural
and artificial objects that are on or near the ground are considered soil
Included are rock, vegetation, minerals, asphalt, glass and even
paint.
52. Why
is soil considered as evidence?
Every Soil is
unique- no 2 places on earth have the exact same soil. Soil from 1 location will
be different from another.
53. What
are Fibers? strands
of threads that make up yarn
54. Why
are Fibers considered as Evidence ?
As you
interact with these products, fibers are released and come in contact with
you. Fibers can connect a victim or suspect to a crime scene
55. What
are the 2 main types of fibers?
Man made (synthetic) and
natural.
56. a.) What
are Natural Fibers?
nThreads
come from plant or animal material
b.) Name
a commonly found natural fiber from plants.
Cotton Threads
come from plant or animal material Cotton, flax – plants Wool, angora, silk -
animals
57. When
collecting fiber evidence, make a Bindle
,
a small paper envelope to store collected crime scene fibers.
58. What
are the 3 layers of Hair?
(1.)
Cuticle,
Hard outside covering that protects the inner layers of hair;
(1)
The
cortex contains the pigment granules that give hair its color ,
CSI’s use
the distribution of these granules to ID hair. The Cortex is made of cells within the cuticle; and the
(3.)
medulla
Made of cells that run through the center of the cortex , like a canal.
59.
What is the Medullary Index? the diameter of the medulla divided by the
diameter of the hair. (ex. Humans= 1/3)
60. How
does the human hair differ from animal ? What measurement is used to distinguish
human hair from animal?
the
Scales and the medullary index
(ratios) for humans (1/3)
are different than animals(1/2)
61. When
cells from the hair follicle can not be collected for DNA, what is located in
the Medulla , that can provide DNA?
Mitochondrial
DNA
62.
Which layer of hair is used to
identify species?
How do animals
compare to humans
it is
ratio or fraction of medulla diameter to hair diameter. Usually, Humans =1/3 and
Animals = ½ .
63. What
are the 4 types of Medulla Classifications?
Continuous,
Interrupted, fragmented and no medulla.
64. Give
2 reasons why fingerprints have been used for identification.
(1.)
Because no 2 people have the same ridge patterns.
(2.)
Fingerprints are impressions created by the ridges on the surface of the skin
(called
65. What
is meant by at latent print?
When a person
touches a surface, oils and perspiration are transferred as an impression. If
not visible, it is called latent (hidden).
66. How
are latent prints need to be made visible on plastic bags?
Use of super
glue fuming to make the print visible, then it is dusted.
67. Which
Ridge Pattern type is the most common?
loop
68. How many points of comparison does an Examiner will need to say they
have matched a fingerprint to an individual?
5-10 points
of comparison to say it is a match
71. a.
What are the 3 types of fingerprint ridge patterns?
1.)loop
2.)whorl
3.)arch
b. Which type is most
common? Loop
72.
Ridge characteristics called _Minutiae_ are the unique details in a
fingerprint ridges, there are up to 150 per print.
73. What is a plastic
print? Give an example of how it may have been created.
it is 3-D ,an individual has touched some type of pliable material ( finger
is pressed into putty, wax, or chocolate, grease)
Packet #3
72.
Restriction fragment length polymorphism is a method in which DNA is converted into a series
of bands that ultimately distinguish each individual for identification in an
criminal investigation.
73. In DNA analysis what
are Restriction Enzymes? Restriction Enzymes are
used to cut DNA into smaller fragments that can then be separated and
characterized for identification.
74.
What is CODIS ?
a. COmbined
DNA
Index System
b. Explain how it works::
National system used for linking serial crimes and unsolved (cold) cases with
repeat offenders through their DNA.
75.
a.) Who is Sir Alec Jefferies? He is credited with
being the first to use DNA profiling using RFLP.
b.) What honor was
bestowed upon him by the Queen of England? He was
later knighted by the Queen of England.
76. What is Electrophoresis? used to separate DNA
fragments. An electrical current is moved through a gel substance causing
molecules to sort by size. The smaller, lighter molecules will move the furthest
on the gel.
77. In the DNA molecule, the four bases are
1. Adenine
2. Cytosine
3. Guanine
4. Thymine
78. The Double helix structure of DNA is
two coiled DNA strands , DNA is
Deoxyribo
nucleic A
cid
79. What are questioned
documents? This branch of Forensic Science involves
the examination of handwriting, ink, paper, etc. to ascertain source or
authenticity as physical evidence.
80. What is Murder? Murder
is defined by common law as the killing of any human being by another with
malice aforethought.
81. What is Manslaughter? ?
Manslaughter
is homicide committed under circumstances not severe enough to constitute
murder, yet it cannot be classified as excusable.
Give and Example ? .v
DUI - Vehicular
82. What is serial murder? when someone kills 3 or
more people and takes a cooling off period in between and when Crimes are
occurring in a pattern that indicates a single offender.
83. What is a spree? Someone who murders people in a
frenzied succession with no cooling-off period in between.
84. What is group-cause murder? Group of people with
a common ideology
b. committed by one or more of
the members
ex. Charles Manson “Family”
85.
What is criminology? The study of criminal character and behavior
(behavioral sciences)
86.
What is a behavioral profile? Describe
the potential suspects – family, lifestyle, age, socioeconomics, physical
appearance
87.
Describe a Disorganized Murder:
a sudden rage or fear of being remembered ,drove them to
kill
killer attacked a random victim in a blind frenzy, the
murderer did not mean to kill his victims, Use a weapon at the scene, and they
leave clues
88.
Describe an Organized Murder:
-
a. killing was planned ( hunting strategy)
b. The killer choose the time and
place
c. Premeditated manner
d. Leave very little clues or
evidence
89.
What is a Modus Operandi??
An offender’s method of carrying out the offense. This evolves over time
90. What is Victimology? a study of victim information to find clues about
the victim selection process
91. Who are forensic psychologist ? use their expertise
with human behavior, motivation, and psychopathology in court and criminal
investigations.
92. ESSAY – Was
convicted serial killer Jeffrey Dahmer an organized or disorganized killer?
Explain your answer and give examples of behaviors that Dahmer exhibited to
support your answer.
a. killing was planned ( hunting strategy)- He never picked someone with a
vehicle, because he did not want anyone to notice a car sitting in one location
for very long. He drugged his victims to gain control.
b. The killer choose the time and
place-he always hunted for victims on Friday nights - so he would
have the whole weekend with his victim. He brought them back to HIS apartment.
c. Premeditated manner- he
planned his hunting strategy.
d. Leave very little clues or
evidence- he had a method of disposing of the bodies - dismember, freeze, and
place bodies in barrels of acid.