Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Trends > Trace Evidence > Flashcards

Trace Evidence Flashcards

1
Q

describe R v Smith 2007

A
  • intruder used the butt of a rifle to break the window of a front door
  • then reached in and opened the front door
  • then shot and killed James Smith
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

true/false a piece of plastic the size of a quarter helped police solve a 2000 murder

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how did a piece of plastic the size of a quarter helped police solve a 2000 murder

A
  • a girl was hit by a car and dragged into the woods and laid into a puddle and she drowned
  • they found shards of glass and a little plastic piece
  • the plastic told them the car was an early 1990s Ford Tempo
  • PO then found a ford tempo that was missing a piece of plastic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Forensic analysis of glass consists of what

A

exam of two or more fragments to determine whether they have a common origin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Identifying broken glass fragments having a common source to the exclusion of all other sources may only be done if they can be what

A

physically matched togegther

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is the most common and important material submitted for forensic trace evidence

A

glass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the composition of window/ bottle glass

A
  • soda lime
  • sodium carbonate
  • calcium carbonate/ calcium oxide
  • silicon oxide
  • Na, Ca, Mg, K, Si, O, C
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is the composition of automobile headlights/ heat resistance glass

A
  • Silicon oxide
  • boron (B)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

true/false glass fragments that may remain on clothing for a long time are very stable

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what does Ri stand for

A

refractive index

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is differentiating glass from plastic done

A
  • by examining relative
  • hardness,
  • solubility,
  • observation with a polarized light microscope
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Once confirmed as glass, the examiner will do what

A
  • perform an analysis of physical properties (color, fluorescence, thickness, curvature, density),
  • optical properties (Refractive Index) and
  • chemical composition
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the order in which glass is analyzed

A
  1. confirm it is glass
  2. analyze physical properties, optical properties, chem composition
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

true/false If a difference between questioned and known samples is found at any point, no further comparison is needed

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the challenges associated w comparing glass fragments

A
  • Most glass evidence is either too fragmentary or too minute to permit a comparison of this type
  • Search for individual properties may be fruitless
  • The general chemical composition of various window glasses within the capability of analytical methods has found to be relatively uniform among various manufacturers - no basis for individualization
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what causes differences in the physical and chemical properties of glass

A
  • Different methods of production
  • variations in composition of the raw materials
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what main physical properties are used to compare glass

A
  • refractive index
  • density
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

true/false Ri and density are class characteristics

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

true/false Ri and density cannot provide the sole criteria for individualizing glass to a common source

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

is there an Ri. database

A
  • they’re working on it
  • the FBI did a bit
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

the Ri value of 1.529 discovered by the FBI was found in how many samples

A

1 in 2200

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

the Ri value of 1.5180 discovered by the FBI was found in how many samples

A

22 in 2200

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

true/false the biggest issue w trace evidence is finding and quantifying it

A
  • false
  • its transfer and persistance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

if there was a car crash and the perp abandoned the car, where should we look for glass

A
  • laundry (clothing)
  • sofa/ chair in living room
  • entryway (could be on shoes)
  • bathroom sink (when cleaning themselves off)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

in her case example of the hit and run, what was the result of the glass they found at his house and the car

A
  • evidence was “indistinguishable”
  • aka a match
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what did the study about glass and pant presence on the clothing and footwear of random people tell us

A
  • more glass was found in the winter than the summer (7% vs 0.9%)
  • about 26% of the clothing was on the upper surface
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what is found in paint

A
  • pigments (for colour)
  • binders/ additives
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what are the diff layers of paint

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

describe the first layer of paint

A
  • electrically applied coat (e-coat)
  • 1st layer
  • applied directly to car
  • epoxy-based, a polymer or resin
  • black or grey colour
30
Q

describe the second layer of paint

A
  • primer
  • second layer
  • epoxy-based
  • polyester chemical or urethane chemical
  • white or pigmented (made to layer well w basecoat)
31
Q

describe the third layer of paint

A
  • basecoat
  • third layer
  • what gives the car colour
  • acrylic polymer
  • also has a binder to hold the paint in place
    (stops from peeling)
32
Q

describe the fourth layer of paint

A
  • clearcoat
  • 4th layer
  • gives the car a glossy finish
  • uncoloured or transparent
  • acrylic polymer or polyurethane polymer
33
Q

how many layers are in a car paint

A
  • most common is 4 (81%)
  • sometimes 5 31%
34
Q

what is looked at at a microscopic exam of paints

A
  • colour,
  • surface texture,
  • colour layer sequence (number and colour of layers)
35
Q

true/false each production plant may use one paint supplier for a particular colour or vary suppliers during a model year

A

true

36
Q

describe the Center of Forensic Science-Paint-Case study

A
  • they testsed 260 paint chips from a wreck yard
  • looked at colour and number of layers via a microscope
  • all samples were distinguishable
37
Q

what are the odds of CS paint originating from another randomly chosen car

A

30 000 : 1

38
Q

what is the PDQ

A

paint data query

39
Q

what does the PDQ allow analysts too do

A
  • obtain information on paints related to automobile
  • make
  • model
  • year
40
Q

what info does the PDQ have that allows analysts to get all this info about the automobile from a paint sample

A
  • colour of paint
  • colour of primer
  • layers
  • binder chem composition
41
Q

what is OEM

A

original equipement manufacturer

42
Q

what is key in the language that is used by experts regarding paint exams

A
  • they “could” have come from the known source
  • no info on the likelihood or frequency
  • can have data to quantify the evidentiary value, but no exact numbers
43
Q

what are the possible outcomes for paint evidence in expert opinion

A
  • differentiated (distinguishable)
  • not differentiated (analytically indistinguishable)
44
Q

what should courts know regarding expert opinion

A
  • rarity of the transferred paint how significant are the findings
  • if the characteristics of the transfer of paint are commensurate w the alleged activity a calm break and enter wont result in someone covered head to toe in paint.
45
Q

fibers can assist in drawing what conclusions

A
  • contact that has occurred
  • how the contact was made
  • how recently that contact took place
46
Q

what is the goal of forensic examination of fibers

A

narrow down the origin to a limited number of sources or even to a single source

47
Q

what is the challenge of forensic examination of fibers

A

mass production of garments and fabrics - limited value of fiber evidence

48
Q

what is the difference between class I and class II fibers

A
  1. natural
  2. manufactured
49
Q

what are some natural fibers

A
  • hair (human or animal)
  • cotton: plant based source
  • wool: animal based source
50
Q

what are some manufactured fibers

A
  • polyester
  • acrylic
  • nylon
  • spandex
51
Q

what is the most commonly used thing to examine fibers

A

optical microscopy

52
Q

what do we use optical microscopy for

A

comparison of standard/reference fibers

53
Q

what is noted when comparing fibers

A
  • Colour
  • morphological characteristics,
  • diameter,
  • striations,
  • pitting,
  • particles presence
54
Q

true/false optical microscopes can differentiate fibers w the same colour

A

false

55
Q

what is the order of examining fibers

A
  1. optical microscopy (colour, diameters, striations etc)
  2. dye composition
  3. chem composition
56
Q

what do we look for when comparing the chem composition of diff fibers

A
  • diff chem structures
  • polymeric structure
57
Q

what is level 1 vs level 2 chem composition comparisons

A
  • level 1 Confirm that all fibers involved belong to the same broad generic class
  • level 2 Confirm that all fibers belong to the same subclassification within their generic class
58
Q

what are individual characteristics of shoe prints/ tire tracks

A

-cuts, scratches, gouges, holes, or
-random inclusions that result from manufacturing, such as bubbles, and
-those that result from adherent substances, such as rocks, chewing gum, papers, or twigs.

59
Q

true/false shoeprint databases exist

A

yesrue

60
Q

describe the R v Mercer 2007 case

A
  • 30cm from victims head (larochelle), there were 2 bloody partial shoeprints
  • PO matched these to mr mercer’s sandles
61
Q

what does “identification” mean

A

definite conclusion of identity

62
Q

what does “probably made” mean

A

very high degree of association

63
Q

what does “could have made” mean

A

significant association of multiple class characteristic

64
Q

what does “inconclusive” mean

A

limited association of some characteristics

65
Q

what does “probably did not make” mean

A

very high degree of nonassociation

66
Q

what does “elimination” mean

A

definite exclusion

67
Q

what does “unsuitable” mean

A

lacks sufficient detail for a meaningful comparison

68
Q

describe how tire tracks were used in the testimony at the Aaron Hernandez trial

A
  • four stones were in the rear passenger side tire of a car he used
  • this created an “anomaly” in the tread pattern
69
Q

describe how tire tracks were used in the Jacob Wetterling case

A
  • there were a myriad of tire tracks and shoe prints where he was last seen
  • Danny Heinrich’s tires were used for search warrants
  • Heinrich had just confessed to an unrelated murder as part of a plea, and turned over his shoes and the tires of his car
  • the FBI lab found a “general match” of these prints
  • they corresponds in design but due to lack of sufficient detail an exact match could not be made
70
Q

describe the R v Hilaire 2018 case

A
  • Nevin was struck by a ford pickup truck when riding his bike
  • he died instantly
  • they found paint chips on his undershirt, tshirt
  • these paint chips were similar in all aspects to the paint in the hood of the truck
  • they found fibers in the right front quarter panel of the truck and hood of the truck, matching his shorts and udnerwear
71
Q
A

Trends (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions