Exam 5 Flashcards
(143 cards)
1
Q
Bloodstain Pattern Analysis: Definition
A
Study of “static” bloodstains.
Normally associated with aftermath of a violent event.
Provide information specific to events occurred.
2
Q
Bloodstain Pattern Analysis: Explanation Provided
A
Provides the “what” instead of “who” of the crime.
Ability to define events that could/not have occurred during bloodshed.
3
Q
Bloodstain Pattern Analysis: Determinations
A
Direction a stain was traveling.
Angle of impact.
Distance above a target surface the stain originated.
Type of force used.
Number of blows.
Position of suspect or victim during attack.
4
Q
Bloodstain Pattern Analysis: History
A
Referenced from as far back as 1894 Germany.
1950’s US impact angle research begins.
Early 70’s Herbert MacDonnel.
1983 International Association of BPA formed.
5
Q
Herbert MacDonnel
A
“Grandfather” of BPA.
Searched all over the world and through history for information and research on BPA then compiled it into a book in early 70’s.
6
Q
Bloodstain Pattern Analysis: Limitations
A
Requires extensive training and experience.
Should not be done with limited stains, need multiple samples.
Only provides parameters and estimates.
Few true absolutes.
7
Q
Bloodstain Pattern Analysis: Experimentation
A
BPA is reproducible phenomenon.
Same physical laws apply to blood s fluid.
Conduct experiments to achieve similar and predictable results.
8
Q
Bloodstain Pattern Analysis: Physics
A
Surface tension, viscosity, gravity, and laws of physics apply equally.
Don’t need to understand physics, just recognize result.
9
Q
Shape of Blood Droplets
A
Retain spherical shape in flight due to:
Surface tension.
Molecular bonding causes liquid to occupy smallest possible space (sphere).
Retains shape until acted upon by other forces.
If not a sphere, could not calculate trajectory.
10
Q
Characteristics of Blood Droplets
A
Keeps volume, stays together.
Does not spontaneously degenerate from low velocity droplets to fine mist.
11
Q
BPA Contact Surfaces
A
Target surface most critical element.
Smoother surfaces provide most usable stains.
Rougher surfaces cause stains to distort.
Distorted stains eliminate value of stain for deciphering information.
12
Q
Uses of Bloodstain Evidence
A
Directionality.
Impact angle.
Type of force.
Number of blows struck.
13
Q
Bloodstain Pattern Directionality: Primary Stains
A
Inertia caused by motion of droplet forces wave of blood to form.
Wave wells up on opposite point from where stain struck.
Stain points to direction of source.
14
Q
Bloodstain Pattern Directionality: Secondary Stains
A
If wave breaks off parent stain, a satellite is formed.
Satellite stain will point back towards parent stain.
15
Q
Blood to Surface Contact
A
When blood hits an object, it does not explode, it runs out.
Creates a right angle at contact.
Triangle exists between target surface and line of travel.
Mathematical principles used to determine impact angle.
16
Q
Bloodstain Pattern: Angle
A
Elliptical stains most helpful for calculating angles.
Correlating impact angles of several stains creates umbrella below which incident must have occurred.
17
Q
Bloodstain Pattern: Quantity
A
Using a number of well-formed stains help establish pararmeters under which the stain was created.
18
Q
Well-formed Stain
A
A stain if divided along it’s axis the opposite sides are approximately equal.
19
Q
Characteristics of Blood in Motion
A
Blood does not travel in straight line (parabola effect).
Angle at which blood travels can increase but never decrease.
Can decrease in speed but never increase.
20
Q
Bloodstain Pattern: Force
A
Low velocity.
Medium velocity.
High velocity.
21
Q
Bloodstain Pattern: Low Velocity
A
Result of normal gravitational force.
Energy of 5 ft. per second.
Size of spatter relatively large, 4 mm or larger.
Passive bleeding (nose, cut finger, etc).
Helps track movement.
22
Q
Bloodstain Pattern: Medium Velocity
A
Result of force or energy in excess of 5 ft. per second to no more of 25 ft. per second.
Size of spatter ranges between 1-4 mm.
Typical of blunt force trauma.
23
Q
Bloodstain Pattern: High Velocity
A
Result of force or energy in excess of 100 ft. per second.
Stains mist in size ranging from 1 mm or less in size.
Usually result of gunshot injuries.
24
Q
High Velocity Exclusions
A
Expiratory blood.
Continued explosion.
High speed machinery.
25
Expiratory Blood
Spitting out blood.
| Blood is deluded with air bubbles and other liquid.
26
Bloodstain Pattern: Velocity Overlap
No specific separation between velocities.
| Some overlap exists.
27
Bloodstain Pattern: Velocity
Refers to speed of instrument creating injury and NOT the speed of blood in flight.
28
Bloodstain Pattern: Number of Blows
Relies heavily on cast off stains.
Count cast off stains to help determine number of blows.
Add one as the first blow is unlikely to have much excess blood for casting off.
29
Cast Off Stains
Help determine number of blows in blunt force trauma injuries.
Produced from blood coming off swinging object.
Occur as trails.
Counting cast off stains and grouping them into forward and backward swings make number of blows apparent.
Possible to tell which hand was used.
Can get on back on perp.
30
Bloodstain Pattern: Size
Helps determine velocity.
| Helps give guess as to what object was used.
31
Bloodstain Pattern: Reconstruction Phenomenon
Void effect or ghosting.
Transfer patterns.
Skeletonization.
32
Bloodstain Pattern: Skeletonization
Blood begins to dry in 50 seconds.
Blood dries from the outside in.
A ring begins to form on outer edge of droplet, which is skeletonization.
33
Bloodstain Pattern: Void Effect / Ghosting
Something has been removed that had blocked path of blood to target surface.
34
Bloodstain Pattern: Transfer Pattern Tyoes
Wipe.
Swipe.
Transfer.
35
Bloodstain Pattern: Wipe
Run object through blood.
| Example: Using clean cloth to wipe up blood.
36
Bloodstain Pattern: Swipe
Blood-covered object is wiped on something else.
Less blood is seen.
Example: Bloody knifed wiped on towel.
37
Bloodstain Pattern: Transfer
Bloodied surface comes in contact with another.
| Example: Bloody shoe prints, hand prints, hair swipe.
38
Bloodstain Pattern Analysis: Cautions
Do not make evaluation based on only one stain.
Not always possible to obtain all types of info needed.
Conclusion must be considered against the relationship of all other evidence.
Won't understand everything, find what you do and start there.
39
Bloodstain Pattern Analysis: Documentation
Notes.
Sketches.
Photographs.
Video tape.
40
Bloodstain Pattern Analysis: Presentation/Analysis Methods
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Powerpoints.
Video tape.
Projection sketch.
Stringing.
Experimentation.
Computer software.
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41
Bloodstain Pattern Analysis: Photography
Overall 360 degree shots.
Establishing shots with obvious landmarks.
Close-ups, 90 degree angle.
With and w/o scales.
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Bloodstain Pattern Analysis: Photography Close-ups
Macro lens.
2 photographs, with and w/o scales.
2 scales for width and length.
90 degree photographs.
43
Bloodstain Pattern Analysis: Video Tape
Allows for different perspectives.
Enhances relationship of evidence to scene.
Can add quick narration.
44
Bloodstain Pattern Analysis: Projection Sketch
Incorporates all intrinsic parts of evidence.
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Bloodstain Pattern Analysis: Stringing
Run strings from stains based on direction to find point of origin.
Provides graphic illustration of where stains originated.
46
Bloodstain Pattern Analysis: Recovering Evidence
Use fingerprint method for lifting stains.
Dried blood scraping for serology testing.
Cotton swabs to collect wet blood.
47
Bloodstain Pattern Analysis: Bio-hazards
Aids virus.
Hepatitis B.
Wear protective clothing.
Use common sense.
48
Bloodstain Pattern Analysis: Aids Virus
Can survive in liquid state for 15 days.
Refrigeration or frozen increases survival.
Once dried becomes inactive.
1 to 9 ratio of bleach to water mix kills virus in 1 minute.
49
Digital Evidence: Key Facts
1. Many types of crimes involved.
2. Every crime scene is a digital crime scene.
3. Can be fragile.
4. Can be easily altered.
5. Never assume it is destroyed.
50
Digital Evidence: Types of Crimes
Everything from computer to violent crimes.
| Information stored on many different devices.
51
Digital Evidence: Crime Scene
Can be involved in every crime scene.
Storage devices and electronics like thumb-drives, sim cards, printers, GPS, cars, cameras, etc.
All can be found/hidden at crime scenes.
Look for digital evidence in places you'd never think to look (legos!).
52
Digital Evidence: Physical Cautions
Evidence often very fragile.
| Susceptible to magnets, extremes in hot or cold.
53
Digital Evidence: Digital Cautions
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Easily altered (just turning on computer can change files).
Dates, names, content easily changed.
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54
Criminal Uses of Digital Devices
Target of crime.
Instrument of crime.
Repository of evidence documenting crime.
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Computers as Target of Crime
Stealing information.
| Identity theft.
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Computers as Instrument of Crime
Stalking through internet, GPS, etc.
Hacking.
Transactions and communication.
57
Computers as Repository of Evidence
Fake IDs, drug trafficking info, etc.
| Computers can help create timelines for crimes.
58
BTK Killer
Dennis Radar, 1974-1991.
Serial killer caught with floppy disk.
Digital evidence solved 30 year case.
59
Sources of Digital Evidence Information
Metadata.
Temp files.
Embedded file data.
Full email documentation.
60
Digital Evidence: Process
1. Assessment.
2. Acquisition.
3. Examination.
4. Documentation and Reporting.
61
Digital Evidence: Assessment Principle
Digital evidence should be thoroughly assessed with respect to the scope of the case to determine the course of action.
Lots of data, figure out what's important and prioritize.
62
Digital Evidence Assessment: Case
Legal authority.
Consult with case investigator.
Other forensic exams.
Not just data retrieval, need to know about case so you know what to look for.
63
Digital Evidence Assessment: Legal Considerations
Electronic Communications Privacy Act of 1986 (ECPA).
Privacy Protection Act of 1980 (PPA).
USA Patriot Act of 2001.
64
Digital Evidence Assessment: Onsite Considerations
May have to do investigations on site.
| Examples: Massive servers cannot be moved or medical servers need to stay in hospital.
65
Digital Evidence Assessment: Physical Considerations
Packaging, transport, and storage.
Prioritize evidence.
Electromagnetic interference.
66
Digital Evidence Acquisition: Principle
Fragile by nature, can be easily altered, damaged, or destroyed by improper handling or examination.
Special precautions taken to preserve evidence.
Failure to take care may render it unusable or lead to inaccurate conclusions.
67
Digital Evidence Acquisition: Components and Methods
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External.
Internal.
Controlled boot.
Remove storage device.
Software.
Make copies and use algorithm to test and ensure exact unaltered copy.
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68
Digital Evidence Examination: Principle
Different types of cases and media may require different methods of examination.
Examiners should be trained for this purpose.
69
Digital Evidence: Active Data
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Current files and directories.
Metadata = good data.
Recycle bin.
Encoded.
System registry files and logs.
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70
Digital Evidence: Types of Data
Active data.
Ambient data.
Archival data.
Stegonography: Embedded or hidden files (like documents hidden in images).
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Digital Evidence: Ambient Data
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Memory "dumps".
Deleted files.
Unallocated clusters.
Slack space.
Swap files.
Temp files.
Printer spool files.
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72
Digital Evidence Data: Slack Space
Unused space at the end of a cluster.
| Even when some data is overwritten, some may still be recoverable.
73
Digital Evidence Data: Archival
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Tapes.
CDs.
DVDs.
Internet.
Network servers.
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74
Digital Evidence Documenting and Reporting: Principle
Examiner responsible for completely and accurately reporting his or her findings analysis results.
Documentation is an on-going process throughout exam.
Important to accurately record steps taken during exam.
75
Digital Evidence: Documentation
Notes and report.
Write down EVERYTHING that you do/happens.
Both good and bad (damages, alterations, etc.)
Write it down or it didn't happen!
76
Digital Evidence: Documentation Report
Summary of findings.
Details of findings.
Supporting materials.
Glossary.
77
Digital Evidence: Key Aspect
The copying EXACTLY of document to be examined.
Also examine copy, never original.
Run algorithm to ensure clean, unaltered copy.
78
Anthropology
Broadly the study of human beings.
| Lofty goal of understanding all there is to know about human behavior, biology, and culture both past and present.
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Fields in Anthropology
Biological (physical).
Archaeology.
Cultural.
Linguistics.
80
Forensic Anthropology
Application of principles, theories, and techniques from biological/physical anthropology to forensic death investigations.
Sub-discipline of bio/physical anthropology.
81
Forensic Anthropology: Determinations
Identity.
Cause and/or manner of death.
Time since deposition.
82
Time Since Deposition
Used in cases where badly composed or skeletal remains are found.
Time since body exposed to the elements.
83
Putrefaction
Our enemy!
Proteins, carbohydrates, lipids broken down into their basic components (amino acids, water, carbon dioxide, fatty acids).
Produces methane, ammonia, and hydrogen sulfide.
84
Mummification
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Our friend! Preserves evidence.
Dry, hot, or windy environments.
Tissues rapidly dehydrate.
Prevents bacterial proliferation.
Preserves tissues.
Not a lot of mummies in OK!
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85
Saponification
Soft tissue and fat converted to adipocere (whitish/gray).
Formed by decomposition of fatty acids mixing with ammonia and other elements to make insoluble soap.
Occurs mostly in oxygen deprived or wet environments.
86
Forensic Anthropology: Decomposition Issues
All types can quickly make person visually unidentifiable.
DNA may or may not be present in any condition.
If DNA, not always known sample to compare to.
Skeleton and features may persist for years, even decades beyond decay of soft tissue.
87
Forensic Anthropology: Identification Determinations
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Human or animal.
Age.
Sex.
Stature (height).
Ancestry.
Particular pathologies to help in identification.
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88
Forensic Anthropology: Non-Identification Determinations
Indicators to cause or manner of death.
Time since deposition.
Historical or recent.
89
Skeleton
Plastic growing tissue like other bodily systems.
Shape and size affected by genetics, nutrition, biomechanics, and pathology.
Constantly growing and tearing down.
Scaffolding for soft tissue.
Bigger muscles require bigger bones.
90
Skeletal Growth
While growing pieces fuse together at ossification centers to form complete bone.
Happens at fairly regular and predictable rate.
Helps determine age.
91
Skeleton: Children
~400 bones to start.
Long bones start as pieces held together by cartiledge.
Skulls have 44 bones at birth.
92
Age Identification: Accuracy
Dental eruption accurate up to ~12 years.
Long bone measurements up to ~10 years.
Epiphsyeal union up to ~23 years.
Fairly accurate under ~25 years.
93
Age Identification: Misc.
Children easier than adults due to bone development.
| Puberty causes great variation in long bone measurements.
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Age Identification: Epiphsyeal Union
Long bone fusion.
| Happens at fairly regular and predictable rate.
95
Age Identification: Identifiers
Epiphyseal Union.
Dental eruption.
Skull.
Pelvis.
96
Age Identification: Pelvis
Pubic synthesis most accurate because it doesn't move (except in children).
Hard to determine sex without it.
Narrow down to 1-2 years of age.
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Age Identification: Skull
Features give clues to age, sex, and ancestry.
Second best clue for identification.
Narrow down to ~5 years of age.
Sutures close or fuse at particular age ranges.
98
Skull: Sutures
Seams where the bones of the skull come together.
99
Skull: Female Features
Smaller, smoother, and more gracile.
| Rounded, pointed chins.
100
Skull: Male Features
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Muscle ridges, such as nuchal crests, are larger.
Supraborbital ridge more prominent.
Mastoid processes larger.
Frontal sinuses larger.
Broader chins/jaw.
```
101
Age Identification: Stature
Measurements of long bones, metatarsals and metacarpals used to estimate living stature.
Total body method is best, not always possible.
102
Age Identification: Ancestry v. Race v. Ethnicity
Refers to a population's shared genetic traits.
Different than race or ethnicity.
Race is social category imposed by others.
Ethnicity is self-embraced shared cultural identity. Sometimes reflects geographical boundaries and shared genetics.
103
Age Identification: Ancestry Accuracy
50 years ago, much easier due to isolation.
| Today much harder, due to mixing and mobility.
104
Age Identification: Ancestry Identifiers
Dentition on skull most fruitful.
105
Age Identification: Ancestry Issues
50 years ago, much easier due to isolation.
Today much harder, due to mixing and mobility.
Skeletal characteristics do no correlate to skin color.
Genotype not always reflected in phenotype.
106
Age Identification: Ancestry
Hardest to assess.
| Highly important.
107
Forensic Anthropology: Cause of Death
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Not all fatal injuries leave markers on bones.
Strangulation.
Gunshot.
Knife.
Blunt force trauma.
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Cause of Death: Strangulation
Can be determined if hyoid is recovered and shows signs of fracture.
Hyoid keeps airways open.
Doesn't always break.
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Cause of Death: Gunshots
Can be determined if bullet directly contacts bone at entry or exit wound.
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Cause of Death: Knife Wounds
Can be determined if blade made contact with bone.
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Cause of Death: Blunt Force Trauma
Can be determined if trauma severe enough to fracture bone.
112
Forensic Anthropology: Impressions
Can often determine if impressions happend at, near, or after time of death.
Example: Nicked during digging v. blunt force trauma.
113
Forensic Anthropology: Continuing Role
Not all bodies recovered have usable DNA.
Growing undocumented population and increased fatalities at border crossings.
Mass disaster recovery efforts.
Human rights violations.
114
Questioned Documents: Disciplines
Handwriting/printing, obliterations/alterations, indented writing, water marks, torn edge, typewriting, damaged paper, check writing, rubber tire tread, stamps, photocopiers, printing, shoe print.
115
Questioned Documents: Examination
May include physical exam of document and side by side handwriting comparison with known writing to include/exclude identity.
Compare to more than one known sample to account for natural variations.
Can detect forgeries based on details.
116
Questioned Documents: Types of Forgeries
Simulations.
| Tracing.
117
Questioned Documents: Simulating Signature
Free-hand copying.
| Look for angles and hesitations.
118
Questioned Documents: Tracing Signature.
Uses original signature to trace new one.
| Exact match = red flag.
119
Handwriting Analysis: Considerations
Considers shapes, angles, and curves of letters.
Relationships to baseline.
Sequence and number of strokes.
120
Handwriting Analysis: Baseline
Imaginary or printed lines on paper.
| Relationships can ascend, descend, or be straight.
121
Handwriting Analysis: Types of Samples
Request Specimens.
Non-request Specimens.
Both need warrants or subpoena.
122
Handwriting Analysis: Non-Request Specimens
Samples taken from suspect's day-to-day activities.
| Includes checks, letters, planners, receipts, calendars, etc.
123
Handwriting Analysis: Request Specimens
New samples from suspect in custody.
Write many samples to help unmask disguises that are hard to maintain with multiple iterations.
Naturally settle back to natural handwriting.
Can take hours.
124
Handwriting Analysis: Non-Request Specimen Considerations
Writing changes over time, so samples must be contemporaneous with time of crime.
125
Handwriting Analysis: Request Specimen Considerations
Paper quality and size.
Writing utensil used.
Look for disguise, compare with signature, non-uniform appearance.
126
Handwriting Analysis: Request Specimen Process
General handwriting form containing multiple names, numbers, and words.
Verbatim, repeat evidence, letter heights and baseline habits.
Recommend taking verbatim 15-20 specimens.
Exact writing on same type/size of paper and closest utensil.
127
Handwriting Analysis: Determinations
Cannot determine age, sex, race, education, physical ability, disability, character, intent.
No scientific basis for these.
"Graphology" not practiced in crime scene investigation.
Can determine left/right handed.
128
Handwriting Analysis: Photocopied Samples
Not suitable for meaningful exam.
May not represent accurate depiction of original.
Line quality crucial consideration.
Details (like hesitation or pressure) can be lost in copy.
Artifacts or trash marks.
129
Handwriting v. Handprinting
Handwriting is cursive, shows greatest variation.
| Handprinting is printed writing, less variation.
130
Handwriting Analysis: Variation
Everyone has a range of variation within their handwriting.
| Repeated samples can expose range to help with identification.
131
Handwriting Analysis: Indented Writing
Impression created from writing instrument captured on sheets below one that contains original writing.
Detected through ESDA and light source.
132
ESDA
Electrostatic Detection Apparatus.
Detects indented writing.
Sheet that adheres to indentations.
133
Handwriting Analysis: Photocopier Trash Marks
Marks specific to certain copier can help identify machine used.
Copiers can be changed and cleaned, so not always the same.
134
Questioned Documents: Paper Edge Matching
Same as fabric or fracture matching.
Identification method.
Note to notepad, stamps to same stamp book, torn currency.
135
Questioned Documents: VSC
Videospectral Comparator.
Important alternative light source.
Reveals differences in reflective properties of inks and fibers in papers.
Can show matches belonged to match book by fibers.
Reveal/clean-up obliterated handwriting (if different ink is used).
Plastic bags.
136
Dr. Case
Doctor goes on walk with wife.
Calls 911, thinks she's dead.
Find disturbed earth containing bag full of evidence.
Plastic bag matched to bags in kitchen (made from one sheet then cut).
Dr. killed his own wife.
137
Forensic Anthropolgy: Big 4 Determinations
1. Age.
2. Sex.
3. Ancestry.
4. Stature.
138
Forensic Anthropolgy: Sex Determination
Uses pelvic bone and skull for identification.
| Cannot determine in children, all too similar.
139
Skeleton: Adults
All bones fused.
206 bones.
Skull has 8 bones.
140
Digital Forensics Methodology
Search and analyze, not identification or comparison.
Looks for dates, times, info, etc.
Can't put you at computer, only that computer has been used.
141
Bloodstain Pattern Analysis: Considerations
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Shape (direction).
Size (force).
Patterns.
Amount.
Distribution.
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142
Bloodstain Pattern Analysis: Vertical Flow
Excess blood dripping down wall.
143
Bloodstain Pattern Analysis: Impact Spatter
Collection of droplets from source of blood.
