What are the (3) characteristics of distinguishing a cast-off pattern?

What are the (3) characteristics of distinguishing a cast-off pattern?

1. Linear.
2. Bloodstain tails point direction of objects movement.
3. Elliptical shape and far distance due to speed of motion.

What is the definition of a cast-off pattern?

What is the definition of a cast-off pattern?

Answer: Bloodstain pattern resulting from blood drops released from a moving object. E.g. swinging of a weapon back and forth during a stabbing.

What characteristics (4) does an expiated bloodstain pattern show?

What characteristics (4) does an expiated bloodstain pattern show?

1. Varying levels of force.
2. Varying stain sizes.
3. Air bubbles present.
4. Diluted due to saliva.

What is the definition of an expiated pattern?

What is the definition of an expiated pattern?

Answer: Bloodstain pattern resulting from blood forced by airflow out of the nose, mouth or wounds.

Why may projected patterns appear as waves?

Why may projected patterns appear as waves?

Answer: Due to fluctuations in blood pressure e.g. burst of an artery - changes in blood pumping from the heart.

What is the definition of a projected pattern?

What is the definition of a projected pattern?

Answer: Bloodstain pattern resulting from a volume of blood ejected under pressure. E.g. arterial spray.

What information (1) can mist patterns provide in a crime scene?

What information (1) can mist patterns provide in a crime scene?

Answer: Provide information on type of weapon used. Such as a gun which has extreme force applied to it.

What is the definition of a mist pattern?

What is the definition of a mist pattern?

Answer: Bloodstain spray pattern of micro-drops of blood as a result of applied force.

What is the definition of a void pattern?

What is the definition of a void pattern?

Answer: Absence of blood in an otherwise continuous blood trail or bloodstain pattern.

How can distribution of impact patterns provide information of where point of impact was?

How can distribution of impact patterns provide information of where point of impact was?

Impact close to surface - clustered stains.
Impact far from surface - wider distribution of stains.

What are (4) characteristics of an impact pattern made by a blunt force trauma?

What are (4) characteristics of an impact pattern made by a blunt force trauma?

1. 1-4mm drops
2. Elliptoid shape
3. V shape distribution
4. Provide information of relative locations of offender and victim

What is the definition of an impact pattern?

What is the definition of an impact pattern?

Answer: Bloodstain pattern resulting from an object striking liquid blood.

What is the difference between forward spatter and back spatter?

What is the difference between forward spatter and back spatter?

Forward spatter: Blood drops that have travelled in same direction as impact force - outward and away from source.

Back spatter: Blood drops that have travelled in opposite direction of impact force - back towards perpetrator.

What is the definition of impact spatter?

What is the definition of impact spatter?

Answer: Bloodstain pattern resulting from an object striking liquid blood.

What information can a satellite stain provide?

What information can a satellite stain provide?

Answer: Indicates individual or object may've been stationary for a period of time.

What is the definition of a satellite spatter?

What is the definition of a satellite spatter?

Answer: Smaller bloodstain that originated during formation of parent stain as a result of blood impacting a surface.

What are (2) examples of projected pattern spatters?

What are (2) examples of projected pattern spatters?

Answer: Arterial spray and expirated.

What are (2) examples of impact pattern spatters?

What are (2) examples of impact pattern spatters?

Answer: Gunshot and blunt force trauma.

What are secondary spatter stains called?

What are secondary spatter stains called?

Answer: Satellite spatter.

What is the definition of a spatter stain?

What is the definition of a spatter stain?

Answer: Bloodstain resulting from blood drop dispersed through the air due to an external force applied to a source of liquid blood.

What is the difference between pools and saturations of blood?

What is the difference between pools and saturations of blood?

Answer: Pool of blood results from accumulation of blood on a surface.

Saturation occurs through accumulation of blood absorbed through porous material.

What is the difference between a 'swipe' and a 'wipe'?

What is the difference between a 'swipe' and a 'wipe'?

Answer: Swipe is bloody hand swiping across a clean wall.
Wipe is bloody wall with clean hand swiping through.

What information (4) can blood transfer pattern provide?

What information (4) can blood transfer pattern provide?

1. Type of object used/missing
2. Location of object/individual
3. Movement of individual
4. Impression evidence

What is the definition of a transfer pattern?

What is the definition of a transfer pattern?

Answer: Bloodstain resulting from contact between a blood-bearing surface and another surface.

What is the definition of a flow pattern?

What is the definition of a flow pattern?

Answer: Bloodstain pattern resulting from the movement of a volume of blood on a surface due to gravity or moment of the target.

How can direction and shape affect the speed of a drip trail?

How can direction and shape affect the speed of a drip trail?

Answer: Tails of blood stains will indicate direction.
Faster the speed, the blood stains will appear an elliptical shape and appear further apart.

What is the definition of a drip trail?

What is the definition of a drip trail?

Answer: Bloodstain pattern resulting from the movement of a source of drip stains between 2 points.

What is the definition of a drip pattern?

What is the definition of a drip pattern?

Answer: Bloodstain pattern resulting from a liquid that dripped into another liquid, at least one of which was blood. Satellite stains will be present.

What is the definition of a drip stain?

What is the definition of a drip stain?

Answer: A blood stain resulting from a falling drop that formed due to gravity.
E.g. blood dripping from an object.

What are the (2) categories and examples of Passive stains?

What are the (2) categories and examples of Passive stains?

Answer:

Airborne

- Drip stains

Non-Airborne

- Flow
- Transfer stains
- Pool
- Saturation

What are passive blood stains?

What are passive blood stains?

Answer: No force acting on blood drop except gravity e.g. blood dripping from person or object.

How is direction from a blood stain determined?

How is direction from a blood stain determined?

Answer: The pointed end or tail indicated the direction the blood drop was travelling when it landed.

How does direction and angle of impact affect a blood stains overall marking on a surface?

How does direction and angle of impact affect a blood stains overall marking on a surface?

Answer: The more acute the angle (less than 90°), the more elongated the stain will be.

What is the distance and size of blood droplets from a high force of impact?

What is the distance and size of blood droplets from a high force of impact?

Answer: 30m/s.
Gunshot/misting.
Drops with a diameter less than 1mm.

What is the distance and size of blood droplets from a medium force of impact?

What is the distance and size of blood droplets from a medium force of impact?

Answer: 1.5 - 8 m/s.
Blunt force trauma.
Drops with a diameter of 1 - 4 mm.

What is the distance and size of blood droplets from a minimal force of impact?

What is the distance and size of blood droplets from a minimal force of impact?

Answer: 1.5m/s.
Drops greater than a diameter of 4mm.

What are the (3) types of force categories?

What are the (3) types of force categories?

- Minimal force.
- Medium force.
- High force.

How does force affect the shape of a blood droplet?

How does force affect the shape of a blood droplet?

Answer: Greater the force of the impact, the smaller the diameter of the blood stain.

How does height affect the shape of a blood droplet?

How does height affect the shape of a blood droplet?

Answer: The higher the blood source, the less smooth the outer perimeter of blood stain.

How does surface texture affect the shape of a blood droplet?

How does surface texture affect the shape of a blood droplet?

Answer: Smooth surfaces will remain a smooth edging around a blood droplet, whereas rough surfaces may cause satellite spatter to break from parent stain.

What are airborne blood stains?

What are airborne blood stains?

Spherical blood droplets that travel through air from source of blood to a surface following a parabolic flight path.

What characteristics (7) should be documented about blood stain patterns at a crime scene?

What characteristics (7) should be documented about blood stain patterns at a crime scene?

1. Number of blood stains
2. Size range
3. Shape
4. Direction of travel
5. Distribution (linear, v shape)
6. location - specific!

What is hemastix and a disadvantage?

What is hemastix and a disadvantage?

Answer: Plastic strip with a blood reagent material at the tip. The reagent coated tip will turn green if haemoglobin is detected.

Disadvantage: can affect DNA analysis.

What information (5) is to be gathered from a crime scene in terms of documenting bloodstain patterns?

What information (5) is to be gathered from a crime scene in terms of documenting bloodstain patterns?

1. Address of the crime scene.
2. Who requested BPA analyst to attend scene.
3. Who is/has been present at the scene - e.g. paramedics to preserve life before death (can affect pattern analysis and evidence, bloody footprints).
4. Time and date arrived and left the scene.
5. Rough sketch of the house - detail wherever blood is present.

What is involved in the third level of training as a BPA analyst?

What is involved in the third level of training as a BPA analyst?

Answer: Interpret complex patterns, determine and reconstruct sequence of events, estimate origin of impact and testify in court.

What is involved in the second level of training as a BPA analyst?

What is involved in the second level of training as a BPA analyst?

Answer: Identify and document patterns and mechanisms, estimate direction of travel and angel of impact.

What is involved in the first level of training as a BPA analyst?

What is involved in the first level of training as a BPA analyst?

Answer: Identification of bloodstains.

What are the (7) roles qualified to do as a BPA analyst?

What are the (7) roles qualified to do as a BPA analyst?

1. On-call roster.
2. Only asses bloodstain evidence at crime scene.
3. Perform presumptive testing of blood.
4. Peer-review interpretations by/as second analyst.
5. Prepare statements
6. Testify in court
7. Instruct evidence recovery staff

What is the role of SWGSTAIN?

What is the role of SWGSTAIN?

Answer: Group of BPA experts from across the world that discuss and evaluate methods, techniques, protocols and research to develop guidelines of best practise for BPA.

What does the acronym 'SWGSTAIN' stand for?

What does the acronym 'SWGSTAIN' stand for?

Answer: Scientific Working Group on Bloodstain Pattern Analysis.

What is the definition of 'Bloodstain Pattern Analysis'?

What is the definition of 'Bloodstain Pattern Analysis'?

Answer: Examination of the location, size, shape and distribution of bloodstains, using science to provide information on the events that resulted in the deposition of bloodstains.