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Forensics > Exam 1 > Flashcards

Exam 1 Flashcards

1
Q

What is forensic science?

A

the application of science to those criminal and civil laws that are enforced by police agencies in a criminal justice system
Also called criminalistics

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2
Q

sir arthur conan doyle

A

Popularized physical detection methods in a crime scene
Developed the character Sherlock

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3
Q

mathiew orfila

A

father of forensic toxicology

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4
Q

Calvin Goddard

A

1891-1966
Used a comparison microscope to determine if a bullet was fired from a specific gun
Published study of tool marks on bullets

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5
Q

edmond locard

A

1877-1966
Locard’s exchange principle states that once contact is made between two surfaces or people, a transfer of material(s) will occur
Study of the material can determine the nature and duration of the transfer

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6
Q

Hoover

A

In 1932, he established a national forensics library to support law enforcement in the US

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7
Q

Oldest american forensics laboratory

A

In LA, created in 1923

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8
Q

stages of death in order

A

rigor mortis
livor mortis
algor mortis

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9
Q

rigor mortis

A

immediately following death, the muscles relax and then become rigid, shortening of the muscles

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10
Q

livor mortis

A

when the human heart stops pumping. The skin will appear dark blue or purple in these lower areas close to the ground

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11
Q

algor mortis

A

the process in which the body temperature continually cools after death until it reaches room temperature, enabling the medical examiner to establish the general time of death

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12
Q

forensic entomology

A

The study of insects and their developmental stages
Can help to determine the time of death by knowing when those stages normally appear in the insect’s life cycle
Determines a person’s time and place of death

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13
Q

what is a crime scene

A

A location where a crime took place

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14
Q

what is evidence

A

Anything presented in support of an assertion

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15
Q

search methods

A

spiral
grid
strip/line
quad/zone

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16
Q

direct evidence

A

Direct evidence is evidence that directly proves a fact, such as a witness’s testimony or a physical object.
Firsthand observation (eyewitness accounts, police dashboard video cameras).
Physical objects: A physical object retrieved from a location, such as a living person or a dead body

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17
Q

circumstancial evidence

A

also called indirect
Evidence that does not, on its face, prove a fact in issue but gives rise to a logical inference that the fact exists
For instance, a suspect in a crime was seen by a witness fleeing the scene on foot after a convenience store robbery
Doesn’t actually prove that this person did the crime

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18
Q

physical indirect evidence

A

Examples of physical evidence include guns, weapons, bodily fluids, a bloody knife or shirt, fired bullets

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19
Q

why is physical indirect evidence good

A

Physical evidence is more reliable than testimonial evidence because it can be tested scientifically and does not lie.
Can actually see and photograph it
Can prove that a crime has been committed
Can corroborate or refute testimony
Can question if witness actually saw it but can’t question if the gun was there
Can establish identity of persons associated with crime
Can allow reconstruction of events of the crime

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20
Q

biological indirect evidence

A

Biological evidence is bodily fluids and tissues that can be used to identify individuals and link them to a crime scene. This evidence can include:
Blood, Semen, Saliva, Skin, Hair, urine, bite mark, plant, pollen
Collected with cotton-tip applicators, clean forceps, and packaged
Not always visible to naked eye

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21
Q

class evidence

A

indirect
A type of physical evidence that is common to a group of people or objects, and can be used to place an individual into a general category such as blood type or gun caliber

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22
Q

individual evidence

A

indirect evidence
evidence that can be linked to a single source, and is considered the best evidence.
Includes tear patterns that match together

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23
Q

examples of individual evidence

A

Fingerprints
Handwriting
Tear patterns that can be matched together
Hair with a ROOT
Broken glass
DNA patterns
Physical matches like broken pieces of glass that fit each other perfectly
Striations on a bullet

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24
Q

7 S’s of crime scene investigation

A

secure the scene
separate witnesses
scan the scene
seeing the scene
sketch form
search pattern
secure collected evidence

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25
Functions of hair
Protection Brows and lashes protect eyes from sweat, dirt, and dust. Nose hair protects nose from germs and foreign objects so we sneeze it out. Skin is protected from sun, dust, and other small particles Thermoregulation Hair stands up and keeps heat close to body. Serves as insulation and protects against friction Sense organ only found in mammals
26
how many hairs shed daily
250. 100 from head
27
2 main types of body hair
shorter and thinner "vellus" hairs (peach fuzz) found on the body The longer and thicker "terminal" hairs. Examples of terminal hairs include the hair on your head, facial hair, eyelashes, eyebrows, pubic hair, chest hair and belly hair
28
in what ways can hair vary
shape, color, length, texture, and diameter
29
arrector pili
tiny muscle surrounding hairs which make them stand up
30
sebaceous glands
secrete lubricating oil for skin and hair, also secretes sebum and slows down bacterial growth on skin
31
Morphology of hair
Shaft (cuticle, cortex, and medulla)
32
cuticle of hair
outside layer, transparent, has protective scales Coronal, spinous, or imbricate Scales always point to tip of hair
33
cortex of hair
middle layer where you find melanin The cortex is the main body of the hair shaft. The color, shape, and distribution of pigment granules (melanin) Provides forensic scientist with points of comparison between individuals
34
medulla
core, most important part to forensic scientist, may be absent The medullary index measures the diameter of the medulla relative to the diameter of the hair shaft Usually less than ⅓ in humans, ½ or greater in animals May be continuous, interrupted, fragmented, or absent
35
coronal scales
crown like, fine diameter, not usually in humans, seen in small rodents and bats
36
spinous scales
petal-like which are usually triangular shaped. Protrude from the hair shaft. Seen in seals and cats, not humans
37
imbricate scales
commonly found in humans, resemble puzzle pieces, overlapping scales
38
medulla in race (African, European, Asian)
African: fragmented or none Euro: fragmented or none Asian: continuous
39
Lanugo
A coat of delicate hairs found on human fetuses preterm
40
vellus hair
fine hair present on the body after birth and before puberty
41
terminal hair
larger, coarser hair of the adult
42
3 stages of hair growth
anagen catagen telogen
43
anagen
follicle actively producing hair and hair will grow
44
catagen
transition phase from anagen to telophase, not actively growing
45
telogen
when the follicle is dormant or resting. Hair routinely falls from skin. Most common type of hair found in crime scenes
46
Detecting DNA in hair roots is most likely in what stage
Anagen
47
How do fibers differ from each other
Chemical properties Cross-sectional shape Surface contour Color Length Diameter
48
types of fibers
animal (protein) plant (cellulose) mineral
49
natural fibers
oldest fibers known to us These are made up of cells cashmere furs, cotton, silk Any fiber that exists as a fiber in its natural state Made of cells which can absorb moisture which makes them very comfortable
50
plant fibers
Seeds Stems Leaves The most common plant fibers encountered in case work are cotton, flax (linen), jute, hemp
51
mineral fibers
Asbestos– a natural fiber that has been used in fire-resistant substances
52
Animal fibers
Hair–wool is most common, can be brushed, clipped, shed, usually from sheep Fur–skin of animal is treated to be flexible and retains the fur, rabbit, mink, and fox Webbing–don’t shed as easily as hair fibers, silk comes from cocoon of caterpillar, fibers are long Scale protrusion!!
53
wool
commonly from sheep and most commonly used animal fiber Finer woolen fibers used in clothes, coarse used in carpets look at degree of scale protrusion and diameter
54
Silk
insect fiber that is spun by a silkworm to make its cocoon Take cocoon, treat it, makes silk Fibers are very long
55
synthetic fibers
produced solely from synthetic chemicals and include nylons (made by dupont, 2nd most common synthetic, polyesters (most popular synthetic fiber), acrylics, spandex, acetate, rayon
56
What makes fabrics unique
Color, size, shape, microscopic appearance, chemical composition, and dye content Very unlikely for two people to wear the same fabric
57
Physical characteristics of fiber are examined by
Calculating density of fiber Oxidation test (burn the fiber to evaluate ash, behavior of flame, and smells)
58
chemical characteristics testing of man made fiber
Burning tests—look at ash, odor, color of flame, reaction, size of flame pH Testing Evaluating any residues or component parts within synthetic fibers Chemical Decomposition tests—treat the fiber with strong acids and bases and see how it breaks down
59
chromatography
separates the dye for analysis, accepted in court
60
pollen is most commonly found where
cuff of suspect's pants
61
forensic botany questions
Who was with victim or at the crime scene/near time of death What did the victim eat before dying When was the crime committed/when was a specific person/vehicle/article at the scene How long since it been sine postmortem interval/how long was body buried
62
when did botany become part of FBI training
1993 at national academy at Quantico, virginia
63
first mention of forensic botany
Plato’s Phaedo of 399 B.C Describes sorates’ self administered death sentence of poison hemlock
64
What happened that made forensic botany legally acceptable
Trial of Richard Hauptmann who kidnapped and murdered the son of charles lindbergh
65
assemblages
groups of plants usually dominated by one species
66
assemblages require?
same: Soil Type Wind Altitude Moisture Sunlight Longitude and latitude
67
gastric contents and forensic botany
Cellulose can't be digested! If you open up stomach if victim died recently, cellulose hasn't broken down (in corn and paper) If these plants/cellulose are in last meal, we can estimate PMIs based on degree of digestion
68
pollen vs spores
The male reproductive structure of a seed plant is called a pollen grain, and is as small as a pinpoint. A spore is the reproductive structure of fungi. both have jagged edges so it attaches easily can survive for decades Both studied under a microscope and have resistant cell walls
69
cellulose
plant wall
70
forensic palynology
the study of pollen and powdered minerals (and spores)
71
how is the plant kingdom classified
seed and non seed earliest plants like ferns and mosses were non-seed, produced by dispersing spores
72
seed plants
Predominant land plants, most likely to leave evidence at a crime scene gymnosperms and angiosperms Produce cones or flowers
73
gymnosperms
oldest seed plants conifers pollination (males produce seeds/pollen, wind brings it to female cone) no fruits includes pines and evergreens
74
conifers
largest, most familiar gymnosperm
75
angiosperms
corn, oaks, maples, and the grasses have flowers produce seeds in a fruit very diverse and seen in almost every habitat, and therefore at almost every crime scene
76
pistil and stamen of flower
pistil is female and produces eggs stigma is sticky, pollen lands here style is a tube which leads to ovary stamen is male and responsible for pollen production filament is long stalk, elevates the anther that produces pollen when pollination occurs, goes to stigma, sticks there, goes down the style and into ovary, fertilizing the plant. Ovary develops into a fruit petal attracts pollinators sepal is leafy part under petals
77
cross pollination vs self pollination
cross: 2 distinct plants self: pollen to stigma within same flower
78
Endospores
Several types of bacteria that make endospores can cause diseases Anthrax and botulism
79
pollen and spores as evidence
Larger pollen grains such as that of corn cannot travel far and can only drift with the wind about a ½ mile Size, shape, surface texture, thickness of wall Someone with cornflower or corn pollen was probably near a corn field
80
Fingerprints also known as
Dactylography/oscopy
81
Dactyloscopy
Study of fingerprints for id purposes
82
1880s fingerprints
Sir francis galton and sir E.R. henry developed the classification system for fingerprints that we use today (Galton-Henry method)
83
1999 fingerprint history
FBI developed the automated fingerprint id system (AFIS) provides automated fingerprint searches, storage of photo files, and exchange of fingerprints and test results Not only for criminals, employment, licenses, and social service programs
84
How many ppl in the country have their fingerprints recorded on AFIS
1 in 6 ppl
85
Fingerprint analysis in 1995 vs today
1995: 1 in 5 exams make a false ID Today: reviewed by 2 examiners. 98.6% for one finger and 99.6% on two
86
Friction ridges
Small ridges that are raised portions of the skin, arranged in connected units Formed at 10 weeks in utero (3 inches long)
87
Changing fingerprints
Stays the same forever unless permanent scars or skin disease
88
What layer affects fingerprints
Basal layer, grows faster than others
89
Sweat glands alternative names
Aporcine and eccerine
90
Apocrine glands
Associated w hair follicles
91
Eccrine glands
Found on ridges of hands and feet
92
Arches, whorls, and loops
Arch: Can be plain or tented gentle slopes Loops: Radial (thumb) or ulnar (pinky). Most common type Whorls: most complex, circular patterns
93
Core vs delta
Core: center of loop or whorl Delta: triangular region
94
Minutiae
Points where print ridges come together or end, considered to be the uniqueness of an individual Primary basis for fingerprint ID
95
How many common minutiae can people have
No more than 8
96
How to match fingerprints
12 match guideline
97
Patent fingerprints
Visible prints Left on a smooth surface when liquids come in contact with the hand and then transferred onto surface Clearly recognizable and needs no processing
98
Latent fingerprints
Caused by transfer of oils and other body secretions onto a surface Not seen easily Requires additional processing to be rendered suitable for comparison Processing is also called development or enhancement Dusting is most common
99
Ninhydrin
Chemical that bonds with amino acids in fingerprints Produces blue or purple color Used to lift prints from surfaces such as paper or cardboard takes 1-2h to develop (heat and humidity make it faster) and lasts 24-48h Used since 1910
100
Cyanoacrylate fuming method
Often called super glue method Procedure to develop latent fingerprints Super glue is heated to produce a fume and yields an off white colored print use of heat and humidity speeds process Worked on interior of car
101
Silver nitrate
Reacts to salt deposits in sweat Once prints develop, should be photographed and removed from light source
102
Iodine fuming
Not permanent Dirty brown colored print and needs to be photographed quickly bc it fades
103
Plastic prints
Impression left in soft material Also called impression or indentation print

Forensics (4 decks)

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