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Questions and Answers
The _____, _____, and ______ of bloodstains may be useful for ____ and _____ the events that produced the bleeding.
The _____, _____, and ______ of bloodstains may be useful for ____ and _____ the events that produced the bleeding.
location, distribution, appearance; interpreting, reconstructing
What is very important in the interpretation of bloodstain patterns?
What is very important in the interpretation of bloodstain patterns?
surface texture
The harder and less porous the surface is, the ____ spatter.
The harder and less porous the surface is, the ____ spatter.
less
The _____ of travel of blood striking an object may be discerned by the stain's shape.
The _____ of travel of blood striking an object may be discerned by the stain's shape.
The _____ end of a bloodstain always faces its direction of travel.
The _____ end of a bloodstain always faces its direction of travel.
How can the angle of impact be measured on a flat surface?
How can the angle of impact be measured on a flat surface?
A drop of blood striking a surface at 90 degrees produces a nearly _____ stain.
A drop of blood striking a surface at 90 degrees produces a nearly _____ stain.
As the angle of the stain decreases, the stain _____ .
As the angle of the stain decreases, the stain _____ .
The _______ of blood drops increases as height increases.
The _______ of blood drops increases as height increases.
What pattern occurs when an object impacts a source of blood?
What pattern occurs when an object impacts a source of blood?
What type of spatter travels away from the source of blood and in the same direction as the force that caused it?
What type of spatter travels away from the source of blood and in the same direction as the force that caused it?
What is produced when blood is projected backward toward the source of the force?
What is produced when blood is projected backward toward the source of the force?
What does an entrance wound do in terms of blood deposition?
What does an entrance wound do in terms of blood deposition?
As the force of the impact _____, the velocity of the blood drops produced increases.
As the force of the impact _____, the velocity of the blood drops produced increases.
As both force & velocity of the impact increase, the diameter of the blood drops _______.
As both force & velocity of the impact increase, the diameter of the blood drops _______.
What type of spatter produces large, separate or compounded drops with diameters 3 mm or greater?
What type of spatter produces large, separate or compounded drops with diameters 3 mm or greater?
What type of spatter produces small drops with diameters from 1-3 mm?
What type of spatter produces small drops with diameters from 1-3 mm?
What type of spatter produces very fine drops with diameters 1 mm or less?
What type of spatter produces very fine drops with diameters 1 mm or less?
What type of spatter is often produced by gunshot exit wounds or explosions?
What type of spatter is often produced by gunshot exit wounds or explosions?
What defines the area on a two-dimensional plane from which blood drops meet?
What defines the area on a two-dimensional plane from which blood drops meet?
How can the area of convergence be established?
How can the area of convergence be established?
What indicates the area in a three-dimensional space from which blood was projected?
What indicates the area in a three-dimensional space from which blood was projected?
The area of origin shows the _____ of the victim or suspect in space when the stain-producing event took place.
The area of origin shows the _____ of the victim or suspect in space when the stain-producing event took place.
The area of origin gives general _____ between blood source to blood-stained surface.
The area of origin gives general _____ between blood source to blood-stained surface.
As distance from the area of origin surface _____, the distribution and distance between drops increases.
As distance from the area of origin surface _____, the distribution and distance between drops increases.
What type of spatter typically produces both forward and back spatter?
What type of spatter typically produces both forward and back spatter?
In gunshot spatter, if the bullet does not exit the body only ____ _____ is produced.
In gunshot spatter, if the bullet does not exit the body only ____ _____ is produced.
Finding ____ _____ ____ containing the victim's blood on a suspect can help investigators place the suspect in the vicinity of the gunshot.
Finding ____ _____ ____ containing the victim's blood on a suspect can help investigators place the suspect in the vicinity of the gunshot.
What is the drawback effect in forensics?
What is the drawback effect in forensics?
What occurs when a blood-covered object flings blood in an arc onto a nearby surface?
What occurs when a blood-covered object flings blood in an arc onto a nearby surface?
When does cast off spatter commonly occur?
When does cast off spatter commonly occur?
Blood from a small or sharp object will produce ____ drops.
Blood from a small or sharp object will produce ____ drops.
Blood from a blunt or large object will produce ____ or _____ drops.
Blood from a blunt or large object will produce ____ or _____ drops.
What can determine if the blow was going from left to right or in the reverse?
What can determine if the blow was going from left to right or in the reverse?
Cast off spatter shows the ____ number of blows delivered to a victim; each blow produces a _____ _____.
Cast off spatter shows the ____ number of blows delivered to a victim; each blow produces a _____ _____.
What type of spatter is produced when a victim suffers an injury to a main artery or the heart?
What type of spatter is produced when a victim suffers an injury to a main artery or the heart?
What causes blood to spurt out of injured areas in arterial spray spatter?
What causes blood to spurt out of injured areas in arterial spray spatter?
What pattern is expelled from the mouth or nose from an internal injury?
What pattern is expelled from the mouth or nose from an internal injury?
What do expirated blood patterns provide clues about?
What do expirated blood patterns provide clues about?
What is created when an object blocks the deposition of blood spatter onto a target surface or object?
What is created when an object blocks the deposition of blood spatter onto a target surface or object?
What can void patterns provide clues about?
What can void patterns provide clues about?
What produces this kind of stain when an object with blood on it touches one that does not have blood on it?
What produces this kind of stain when an object with blood on it touches one that does not have blood on it?
What do contact/transfer patterns include?
What do contact/transfer patterns include?
What are patterns made by drops of blood flowing by the pull of gravity?
What are patterns made by drops of blood flowing by the pull of gravity?
What may flow patterns come from?
What may flow patterns come from?
What do flow patterns demonstrate?
What do flow patterns demonstrate?
What occurs when blood collects in a level and undisturbed place?
What occurs when blood collects in a level and undisturbed place?
The approximate drying time of a pool of blood is related to the ______ _____ of the scene.
The approximate drying time of a pool of blood is related to the ______ _____ of the scene.
What is a series of drops that are separate from other patterns, formed by blood dripping off an object or injury called?
What is a series of drops that are separate from other patterns, formed by blood dripping off an object or injury called?
What may drip trail patterns form?
What may drip trail patterns form?
The tails of drops will point in the _____ the person was moving.
The tails of drops will point in the _____ the person was moving.
Investigators should note, study, and photograph each ____ and ____ of blood at a crime scene.
Investigators should note, study, and photograph each ____ and ____ of blood at a crime scene.
What type of documentation should show the whole pattern and relationships between stains?
What type of documentation should show the whole pattern and relationships between stains?
What type of documentation should show the dimensions of individual stains with a ruler next to the stain?
What type of documentation should show the dimensions of individual stains with a ruler next to the stain?
The _____ ____ ____ determination should be noted whenever possible and all measurements and calculations of angles should be recorded in the crime scene notes.
The _____ ____ ____ determination should be noted whenever possible and all measurements and calculations of angles should be recorded in the crime scene notes.
Study Notes
Blood Spatter Analysis
- Bloodstains' location, distribution, and appearance are crucial for interpreting and reconstructing events related to bleeding.
- Surface texture significantly influences bloodstain pattern analysis.
Bloodstain Characteristics
- Hard, less porous surfaces produce less spatter.
- The direction of blood travel can be determined by the shape of the stain.
- The pointed end of a bloodstain indicates its direction of travel.
Impact and Angle
- The angle of impact can be assessed by the circular distortion of a stain on a flat surface.
- A blood droplet striking a surface at 90 degrees results in a nearly circular stain.
- As the angle decreases, the bloodstain appears elongated.
- The diameter of blood droplets increases with height.
Types of Spatter
- Impact spatter arises when an object contacts a blood source, disseminating blood outward.
- Forward spatter moves away from the blood source in the direction of the impact force.
- Back spatter projects toward the source of the force, typically seen in entrance wounds.
Velocity Classification
- Low velocity spatter: large, separate drops (3mm+), caused by slow-moving forces (<5 ft/sec).
- Medium velocity spatter: smaller drops (1-3mm), associated with blunt force trauma (5-25 ft/sec).
- High velocity spatter: very fine droplets (<1mm), produced by rapidly traveling forces (≥100 ft/sec), often linked to gunshot wounds.
Convergence and Origin
- The area of convergence is identified by drawing lines through the long axes of bloodstains to find intersections.
- The area of origin signifies the spatial origin of where blood was projected, indicating the victim's or suspect's position during the event.
- Greater distance from the area of origin typically increases the distribution and spacing of blood drops.
Gunshot Spatter Dynamics
- Gunshot spatter usually creates both forward and back spatter.
- If a bullet does not exit, only back spatter is produced.
- Finding high velocity spatter containing victim’s blood on a suspect helps establish their proximity to the crime.
Other Spatter Patterns
- Drawback effect occurs when a shooter's blood splatters back onto them, indicating their presence at the scene.
- Cast off spatter results when a bloodied object swings, flinging blood onto surfaces.
- The characteristics of the object (small/sharp vs. blunt/larger) affect the size and spread of drops.
Spatter Evidence
- Arterial spray spatter occurs from injuries to major arteries, with blood spurting under pressure.
- Expirated blood patterns emerge from the mouth or nose, providing injury-related clues.
- Void patterns arise when an object blocks blood deposition, aiding in reconstructing crime scene elements.
- Contact/transfer patterns result from bloodied objects touching non-bloodied surfaces, including prints.
- Flow patterns indicate the movement of blood influenced by gravity, often originating from spurt injuries.
Documentation Practices
- Investigators should observe, study, and photograph every pattern and drop of blood.
- Medium range documentation should capture entire patterns and relational placement of stains.
- Close-up documentation must show individual stain dimensions with rulers for measurement accuracy.
- Area of origin measurements and angle calculations should be meticulously recorded in crime scene notes.
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Description
Test your knowledge of blood spatter analysis with this collection of flashcards from Forensics Chapter 10. Learn key terms and concepts related to the interpretation and reconstruction of bloodstain patterns. Perfect for anyone studying forensic science and its applications in crime scene investigations.
