Ch 4 Physical Evidence Flashcards

1
Q

What is the greatest possibility of error when searching for weapons at a crime scene?

A

Ignoring common items of furniture or equipment at the scene as suspect weapons

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

The removal of spent bullets without damage to the original condition is an example of what?

A

Postmortem forensic science

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

Valuable evidence that typically gets recognized

A

Bloodstains on clothing and other objects

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

Blood splashes and and blood drops help to narrow ….

A

The size of the suspect group,
Support identity when a an sp is located,
And plot the movements of the v and the assailant

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

Relatively fresh bloodstains generally appear to be ….

A

Reddish-brown in color

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

The question that often must be answered of bloodstains?

A

Whether the stain is blood or some other substance

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

How is the determination of whether or not a stain is blood?

A

Preliminary test color, kastle-Meyer color test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

This test is based on the reaction with enzymes in the blood which causes the test strip to turn a deep pink color

A

Kastle-Meyer color test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Theses test strips are a useful presumptive field test for blood

A

Hemastix

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

Test strips used with the Kastle-Meyer color test

A

Hemastix

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

Theses are a useful presumptive field test for blood

A

Hemastix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Drop sizes of blood increases with the

A

Distance of the fall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The tails or pointed ends on bloodstains indicate

A

The direction of movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The round edges of blood stains face

A

The source of the bleeding

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

Another ? That must be answered is whether at one time blood was present at the crime scene…

A

And has since been cleaned up

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Presumptive test that uses light rather than color as it reacts with blood

A

Luminol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Luminol helps identify whether blood at a scene…

A

Was cleaned up

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Faint blue glow after spraying luminol

A

Luminescence

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

New trademark name that may be used in place of luminol

A

Bluestar

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

T/f

A room does not need to be darkened in order to use luminol

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Advantage of bluestar over luminol

A

It’s reaction with a bloodstain can be observed without having to create complete darkness

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

Both of these presumptive tests are extremely sensitive and are capable of detecting bloodstains diluted up to 100,000 times

A

Blue star and luminol

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

Final determination in blood evidence

A

Whether it is human or animal origin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

These tests are based on the reaction when animals, usually rabbits, are injected with human blood

A

Precipitin test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

This test involves an injection that causes antibodies to form that react with human blood to neutralize its presence

A

Precipitin test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Another type if precipitin test is?

A

Gel diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

This test takes advantage of the fact that antibodies and antigens diffuse or move toward on another on a plate coated with a gel medium made rom polymer called agar

A

Gel diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Gel medium made from a polymer

A

Agar

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

In gel diffusion , if a blood stain is human…

A

A line of precipitation forms where the antigens and antibodies meet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

This type of test in determining whether blood is human is very sensitive and only requires a small amount of blood

A

Gel diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

This type of test may still give a positive precipitin result on a blood stain that is 10-15 yrs or older blood

A

Gel diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Personal imprints and impressions found at crime scenes identify or tend to identify a person or vehicle….

A

As having been at the crime scene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Markings left on a surface by protruding parts of a person or a vehicle?

A

Imprints

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Below are examples of what?
Bloody handprints, footprints,
Tire tread marks left behind after the tire has been contaminated with oil or mud

A

Imprints

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What are the Steps of evidence retrieval of imprints

A

First photograph
Lifted by dusting with contrasting powder
Apply clean, sticky, transparent tape to dusted area to pick up
Press tape to a clean card to preserve it
*the object with the imprint sometimes can be transported to the laboratory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

These are made by a person or an object in a material softer than the item of evidence making the impression.

A

Impressions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

These are examples of what?

Tire tracks or foot prints in snow or soft dirt

A

Impressions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What clues do A trail of shoe prints or footprints offer?

A

Size or weight of the person making them
Speed of movement
Any gait abnormalities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

This super cooling phenomenon leads to a unique spheroidal formation that is generally not observed in the natural environment.

A

Exothermic reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Fingerprints found at a crime scene can either be ?

A

Imprints or impressions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Bloody fingerprints left on weapons or at the scene of a crime are called?

A

Contaminated prints

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

These finger prints are observable with the naked eye

A

Contaminated prints and plastic prints

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Fingerprints that are impressions that a burglar might leave behind when his or her fingers come into contact with soft glazier’s putty around the edges of a window

A

Plastic prints

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

These finger prints are collected by first photographing then casting with dental plaster

A

Plastic prints

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

These types of prints usually cannot be seen by the naked eye and need to be developed to be seen

A

Latent prints

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

These fingerprints are caused by the transfer of body perspiration or oils present in finger ridges that are deposited on the surface of an object

A

Latent prints

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Two types of surfaces to find latent prints?

A

Porous and nonporous surfaces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Ex of a smooth nonporous surface

A

Glass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Ex of porous surface

A

Paper

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Latent prints on a smooth nonporous surface such as glass can be developed by

A

Dusting with a powder of contrasting color of the surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Latent fingerprints found on porous surfaces such as paper are developed

A

In the laboratory through iodine fuming or ninhydrin process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

When iodine fumes react with the ammo acids in the print, they appear

A

Purple when developed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Testing done on latent fingerprints of a porous surface that are done in the lab, where iodine fumes react with the amino acids in the print and appear purple in color when developed

A

Iodine fuming and ninhydrin process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

T/f

Slippery surfaces such as plastic bags are resistant to the dusting process

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Give an example of where a print may be found that is resistant to the Dusting process

A

Slippery surface of a plastic bag

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

A common glue product when heated in a covered tank resulting in fumes on a fingerprint and makes a print observable and photographable

A

Cyanoacrylate

57
Q

The process in which a common glue is heated in a covered tank resulting in fumes that settle on a fingerprint making the print observable and photographable

A

Cyanoacrylate fuming process

58
Q

Which type of print could be used with the cyanoacrylate fuming process?

A

Latent prints that are left on smooth slippery surfaces such as a plastic bag

59
Q

What does Afis stand for?

A

Automated fingerprint identification system

60
Q

This machine reads prints by placing a persons hands on a platen and a scanner that reads the print digitally

A

Afis

61
Q

Afis has reduced the FBI’s ten- print processing time from?

A

45 days to less than 2 hrs

62
Q

What are the traditional means of ingress of forced entry?

A

Windows, doors, and skylights

63
Q

The Initial procedure for collecting marks of tools used to gain access

A

Locate accurately the impression and record the general description and measurements.

64
Q

What is the key to identifying marks of tools?

A

Accuracy

65
Q

In Tool mark, what could make an effective trial exhibit?

A

Cast impression of mark

66
Q

What is the overriding factor in reporting and collecting tool impressions at the scene of a crime?

A

Preservation of the impression, or it’s reproduction for future comparison with a suspect tool

67
Q

Prevailing practice of tools

A

Treat tools as suspects and collect it for laboratory comparisons

68
Q

T/f

Second contact of a TOOL to an impression ruins the evidence

A

True

69
Q

A form of trace evidence that is transferred between individuals and objects during the commission of a crime

A

Hair

70
Q

Hairs are typically transferred during what type of crime?

A

Personal crimes such as sexual assaults physical assaults and homicides

71
Q

DNA analysis can be performed on hair if

A

The root bulb is still attached

72
Q

In the absence of DNA analysis, the crime laboratory would conduct

A

A microscopic analysis

73
Q

What does A microscopic analysis of hair determine?

A
Origin
Racial origin
Age and sex
Forcible removal
Hair comparison
74
Q

Which type of hair shows little variation and uniform distribution of pigment compared to other body hairs?

A

Head hair

75
Q

The Origin of hair determines

A

What part of the body did the hair come from

76
Q

This type of hair is usually straight or wavy, with fine to course pigmentation which is evenly distributed

A

Racial origin is Caucasian

77
Q

This type of hair is normally curly with an uneven distribution of pigments

A

Racial origin- African American

78
Q

A cross-sectional analysis of Caucasian hair demonstrates that it is

A

Oval to round shape

79
Q

Cross sectional analysis of an African American hair demonstrates that it is?

A

Racial origin- Flat to oval in shape

80
Q

The age and sex of a person’s hair cannot be determined with any degree of certainty with the exception of?

A

Infant hair

81
Q

Why is infant hair an exception of identification of age and sex?

A

It is very fine and shirt and has fine pigmentation

82
Q

When hair has been dyed or bleach, it may give identification of?

A

The sex of an individual, but not certainty of it

83
Q

Examining what part of the hair could I’d whether it was forcibly removed?

A

Examining the hair root and shaft

84
Q

What is more likely to be the result of hair normally falling out than forcible removal?

A

Absence of adhering tissue to the bulbous shape root

85
Q

What is the most common request in hair determination?

A

Whether the hair found on the scene belongs to sp

86
Q

T/f

It is not yet possible to individualize human hair to any single person through its structural characteristics

A

True

87
Q

Hair growth estimate based on time since the hair was treated can be based on what rate?

A

One centimeter per month

88
Q

T/f

Fungal and nit infections can further link a hair specimen to a particular person

A

True

89
Q

Why is the examination of human hair most valuable?

A

It’s ability to exclude someone as a suspect in the commission of a crime.

90
Q

Fibers are key items of evidence in personal crimes such as

A

Homicides, physical assaults, sexual assaults

91
Q

In a case where a victim was bound with Rope, twine, or cloth backed tape, fiber analysis is important in determining?

A

The source of these materials

92
Q

Name the two types of fibers

A

Natural and manufactured fibers

93
Q

List the common natural fibers found

A

Wool and cotton

94
Q

Which natural fiber is plant based?

A

Cotton

95
Q

Name the common synthetic manufactured fibers

A

Nylon, acrylic, polyester

96
Q

What is the first step in the analysis of fibers?

A

Microscopic examination with a comparison microscope

97
Q

This is essentially two microscopes connected together side by side that allows two samples to be viewed simultaneously by the operator

A

Comparison microscope

98
Q

What is used for a reliable method for analysts to compare the colors of fibers through spectral patterns?

A

Visible light micro spectrophotometer

99
Q

Before the forensic scientist can reach a conclusion that two or more fibers compare, it must be shown that the fibers in question have…

A

The same chemical composition which can be determined by the use of infrared microspectrophotmetry technology

100
Q

Name the two types of glass fractures

A

Radial and concentric

101
Q

This glass fracture starts at the center or point of impact

A

Radial fracture

102
Q

To glass fracture runs outward in a star shaped pattern

A

Radial fracture

103
Q

This glass fracture forms concentric circular cracks around the point of impact

A

Concentric fracture

104
Q

The location where the cone shaped crater is narrowest of a bullet that perforated a glass panel, indicates

A

The direction from where the bullet was fired

105
Q

If a number of bullets hit a pane of glass, the sequence can be determined by

A

Examining the radial fractures

106
Q

The radial fractures of the first bullet….

A

Stop by themselves or run to the edge of the glass

107
Q

Subsequent radial fractures produced by other bullets will…

A

Stop at an already present radial fracture produced by the first bullet

108
Q

Describe a fracture match

A

When glass splinters or shards found on suspect fill the void of glass at scene

109
Q

What are some common characteristics examined to differentiate glass?

A

Density, refractive index, thickness, color, and chemical composition

110
Q

Paint evidence is usually found in what form?

A

Smears or chips

111
Q
T/f
Usually only class characteristics can be determine by paint analysis
A

True

112
Q

Which type of paint evidence is more useful?

A

Chips

113
Q

Physical characteristics of paint

A

Color, layering , weathering, texture

114
Q

Chemical properties such as solubility and composition can indicate

A

The type of paint and identify the pigmentation and fillers used in the manufacturing process

115
Q

Paint Reference samples of automobiles help provide

A

Type of car with that paint

116
Q

_— of a bullet hole in a glass window indicates the direction of travel

A

Cratering

117
Q

T/f

A bullet enters from the small side of a crater and exits from the large side

A

True

118
Q

In cases involving checks, the check itself is a ?

A

Questioned document

119
Q

T/f

Documents that have been destroyed or partially destroyed by fire can never be restored by lab technicians

A

False, can sometimes be restored

120
Q

Charred paper must be sprayed with

A

A preservative and requires special packaging and transport to the place of examination

121
Q

What are the two types of proof used at criminal trial?

A

Direct and Circumstantial evidence

122
Q

This type of proof involves eyewitnesses who have, through one or more of their five senses, experienced something relative to the crime

A

Direct Evidence

123
Q

This type of proof is defined as evidence from which an inference can be drawn and which includes items such as physical evidence

A

Circumstantial Evidence

124
Q

What are the major types of circumstantial evidence?

A

weapons, blood, imprints, or impressions, tool marks, hairs, fibers, glass, paint, questioned documents.

125
Q

Name the two categories of Physical evidence

A

Class evidence and individual evidence

126
Q

this type of physical evidence cannot be linked to a particular person or an object but only to a class of object

A

Class evidence

127
Q

Glass, paint, shoe prints, ballistics, fibers, and tool marks are all examples of what?

A

Class evidence

128
Q

firearms should be handled to preserve

A

ballistic identity

129
Q

the identification of firearms, bullets, cartridges, and shotgun shells

A

ballistics

130
Q

refers to the functioning of firearms through the firing cycle

A

interior ballistics

131
Q

the study of projectiles in flight

A

exterior ballistics

132
Q

what do ballistics use as the primary source of identification?

A

the inside of the barrel, the firing pin, the breech face in which the firing pin hole is located, the chamber, and the ejector and extractor.

133
Q

firearms should be picked up by their

A

rough or checkered wooden portions or any external metal portion except the trigger guard and trigger area

134
Q

emblems and symbols are _______ that indicate tests performed to prove the strength of the chamber of a firearm by actual firing with maximum loads

A

proof marks

135
Q

refers to the diameter of the barrel of the gun and is also an identifying characteristic

A

caliber of the weapon ( or its gauge if a shotgun)

136
Q

this test starts with applying adhesive tapes to the person’s hands. These tapes are then sent to the crime laboratory where they are examined using a scanning electron microscope interfaced with an energy dispersive x-ray

A

gsr. gunshot residue examination

137
Q

this examination is used to search for the presence of the major components in a center fire cartridge

A

gsr. gunshot residue examination

138
Q

what are the major components in a center fire cartridge?

A

antimony sulfide, barium nitrate, and lead styphnate as well as metallic particles of zinc copper or nickel.

139
Q

this super cooling phenomenon leads to a unique spheroidal formation that is generally not observed in the natural environment.

A

exothermic reaction