What are the 4 types of passive bloodstains?
Passive bloodstains can be further subdivided to include drops, drip patterns, pools, and clots.
- Passive Bloodstain. Passive Bloodstain on a rough surface (such as wood or concrete)
- Projected Bloodstain. Projected Bloodstain, possibly a Cast-Off Pattern or a HVIS.
- Transfer Bloodstain.
How can you determine the origin of a blood droplet?
By measuring the width and length of a single drop of blood, you can determine the angle of impact. By using the Law of Tangents, you can calculate the height from which the blood fell, or the point of origin for the blood.
What can dried blood tell an expert?
Dry blood samples can detect both antibodies and hepatitis virus RNA successfully. It involves obtaining a few drops of blood by fingerprinting, and letting them dry on a specially specific absorbent paper card.
What Cannot be determined by blood spatter?
Which of the following CANNOT be determined by observing blood spatter? The DNA of the victim. The position of the assailant at the time of the spatter.
Why is it important to determine the point of origin of a bloodstain?
In bloodstain pattern analysis, it is important to know the point of origin (PO) of an impact pattern. Impact patterns were created by means of a modified mouse trap, and subsequently the PO was calculated. By examining the characteristics of single bloodstains, the influence on the deviation could be determined.
What is the difference between the point of convergence and the point of origin?
The source of blood spatter can be localized by following the direction of travel of several stains. What is the difference between the point of origin and point of convergence? Point of origin is in 3D space, point of convergence is in 2D space. Passive – no force applied to blood other than gravity.
What is the difference between splatter and spatter?
To spatter means to scatter small particles of a substance. A spatter is the pattern of drops that result from spattering. To splatter means to scatter large particles of a substance.
What is the difference between the area of convergence and the point of origin?
Area of Convergence – The area containing the intersections generated by lines drawn through the long axes of individual stains that indicates in two dimensions the location of the blood source. Area of Origin – The three-dimensional location from which blood spatter originated.
What type of DNA is easiest to collect?
Mitochondrial DNA, because is found small structures outside the nucleus of a cell and is inherited from the biological mother.
How do you find the point of convergence?
The way to determine convergence at these points is to simply plug them into the original power series and see if the series converges or diverges using any test necessary. This series is divergent by the Divergence Test since limn→∞n=∞≠0 lim n → ∞ n = ∞ ≠ 0 .
What is the difference between a wipe and a swipe?
The difference between swipe and wipe patterns is based on the initial location of the blood prior to the contact between the two surfaces. A wipe pattern is “An altered bloodstain pattern resulting from an object moving through a pre-existing wet bloodstain.”
What is a wipe bloodstain?
A wipe pattern is a bloodstain pattern created when an object moves through an existing stain, removing and/or altering its appearance.
What type of evidence is blood type?
Examples of class evidence include blood type, fibers, and paint. Individual Characteristics are properties of physical evidence that can be attributed to a common source with a high degree of certainty. Examples of individual evidence include anything that contains nuclear DNA, toolmarks, and fingerprints.
What is a void pattern?
In bloodstain patterns, a void is an area that is somehow shielded and thus does not show staining that would otherwise be expected. Also called a shadow pattern, a void pattern can be seen when a person’s body, shoe, hand, etc.
What is a void?
noun. an empty space; emptiness: He disappeared into the void. something experienced as a loss or privation: His death left a great void in her life. a gap or opening, as in a wall. a vacancy; vacuum.
What causes a void pattern?
A void is caused when an intermediate object intercepts the trajectory of blood droplets in flight, while on their way to an otherwise unobstructed final target surface.
What shape do blood droplets form when dropped vertically?
The fluid dynamics of dropping blood are responsible for the stains or patterns produced. The surface tension of the liquid blood causes the blood drops produced from a blood source to be spherically shaped.
What happens to a blood droplet as it impacts a hard surface vs a soft one?
There is less blood splatter from a blood droplet that has fallen on a hard, non porous surface then compared to a blood droplet landing on a soft surface. The most common type of blood stain pattern found at a crime scene is impact spatter.
How do investigators figure out where the victim is located if there is blood evidence on the wall?
Analysts or investigators will typically soak up pooled blood, or swab small samples of dried blood in order to determine if it is human blood and then develop a DNA profile. This becomes critical when there are multiple victims.
What type of spatter creates the largest blood droplets?
LOW VELOCITY IMPACT: SPATTER THAT PRODUCES THE LARGEST BLOOD DROPLETS. PARENT DROP: DROP OF BLOOD THAT CASTS OFF A WAVE OR SATELLITE SPATTER. PLASMA: FLUID PORTION OF BLOOD, OBTAINED BY CENTRIFUGING A SAMPLE OF WHOLE BLOOD. COMPOSED OF 90% WATER, 10% METABOLITES.
What can a void tell a spatter analyst?
What can a void tell a spatter analyst? An object that leaves a void in a bloodstain pattern will have a matching bloodstain pattern on its surface, allowing analysts to replace it in the scene if found. Void patterns are most useful for establishing the position of the victim(s) and assailant(s) within the scene.
Why are blood spatter specialists usually called to the scene?
Bloodstain pattern analysts sometimes are called to gruesome scenes to gather crucial evidence regarding violent crimes. Analysts can determine the trajectory of a projectile, the number of wounds a victim suffered, and how events unfolded during a violent crime.
What is the drawback effect?
gunshot. Describe the drawback effect. When the victim’s blood back spatters onto the gun or shooter, it places them at the scene of the crime. when a blood-covered object flings blood in an arc onto a nearby surface.
What does drawback mean in English?
(Entry 1 of 2) 1 : a refund of duties especially on an imported product subsequently exported or used to produce a product for export. 2 : an objectionable feature : disadvantage The plan’s only drawback is its cost.
What does main drawback mean?
a hindrance or disadvantage; an undesirable or objectionable feature. Commerce. an amount paid back from a charge made.
What does disadvantage mean?
1 : loss or damage especially to reputation, credit, or finances : detriment the deal worked to their disadvantage.