Blood typing and spatter

5 things that a forensic analyst can determine from the blood pattern analysis.

-Determine the direction the blood was traveling -The angle of impact of each blood droplet -The area of origin -Help resolve whether a victim died from a homocide or suicide -General velocity off the blood

Passive bloodstains

-patterns created from the force of gravity. -Drop, series of drops, flow pattern, blood pools

High velocity impact

100 ft./s fine mist spatter pattern Size do droplet - less than 1mm examples-gunshot

Medium velocity impact

25 ft./s Size of droplet -1-4mm example-beating ,stabbing

Low velocity impact

5 ft./s Size of droplet- 4-6mm Examples-blunt object impact (hammer,flashlight)

What can blood spatter do?

A blood spattered can help reconstruct the series or events surrounding a shooting stabbing or beating

Pools

From around victim who is bleeding heavily and remains in one place

Adhesion

Attractive forces of two different objects.starts as teardrop because of adhesion

1939

Bathazard first researcher to analyze the meaning of spatter pattern

Passive fall

Blood falling directly to the floor at 90° angle will provide circular drops with more secondary satellites being produced if the surface it is textured

Cohesion

Blood mixture is attracted to similar blood mixtures and six together, not separate as it falls. Cause droplet to stay together

1955

Blood spatter evidence used in the Sam Shepard case helping to exonerate him

What type of evidence is blood typing? what does that mean?

Blood typing is class evidence because many people share the same blood type and this evidence is used to exclude a person as a suspect.

Spatter

Bloodstains created from the application of force to the area where the blood originated

Trails

Can be left by bleeding victim depositing blood as he or she moves from one location to another

What is the benefit of DNA STP analysis?

It can analyze the WBC and that provides a high degree of certainty regarding whether blood left at a crime scene is consistent or inconsistent with the blood of a particular suspect or victim.

Wipe pattern

Created from an object moving through a bloodstain

What is Kastle-Meyer test?

It detects hemoglobin but can also detect non blood compounds containing nickle and copper.

What is Rh factor?when was it discovered?

Discovered in 1940 by Alexander Welner when he was working with rhesus monkeys. This factor is independent of A and B antigens blood that has the Rh factor is designated Rh+, while blood that doesnt have it is Rh-

1971

Dr.Herbert mcdonnell used blood spatter analysis as tooo in forensic examination

Angle of impact calculations

Sign inverse( width divided by length)

Case study of Ludwig Tessnow

In 1901 two boys went missing many years ago and found professors uhlenhuth who developed a technique to distinguish bloom blood as well as human blood from animal blood. Tessnow clothing was tested and found wood dye, sheep blood and 17 fist traces of human blood. Tessnow was one of the cases to use the precipitlin test and was charged with murder trial, convicted and executed.

Swipe pattern

Is created from an object leaving a bloodstain

Name of doctor that made blood transfusion possible

Karl Landsteiner

Dr Karl Landsteiner discoveries:

Karl Landsteiner found that blood from one person did not always freely mix with blood from another person instead clumping of red blood cells. Karl discovered reactions to a blood antigen other than a persons own can have fatal consequences during a blood transfusion.

Smears

Left by bleeding victims depositing blood as heor she touches or brushes against the wall or furniture

How is blood evidence detected at a crime scene?

Light source-investigators will use UV light or high intensity light. Blood reagent tests-test to detect blood at a crime scene based upon the properties of hemoglobin in the blood

area of convergance

Means you can use this information to calculate the height above the floor at which the injury took place.

Satellite spatters

Small drops of blood to the break of from the parent spatter when the blood droplet hits the surface

Type of blood and % US population

O-43% Rh+ 85% A-42% Rh- 15% B-12% AB-3

Transfer or contact bloodstains

Patterns created when the wet bloody I'll check comes in contact with the target surface. Maybe use to identify an object or body part.

Projected bloodstains

Patterns that occur when a force is applied to the source of the blood

Gravity

Pause it to the ground drop it becomes longer than wide

Examples of reagent test

Phenolphthalein-Chemical used today produces pink color when reacts to hemoglobin. Hemastix- strp that has been coated with tetramethyl bendazide Luminol- used to detect traces of blood even if it's cleaned or removed. Fluorescein- capable to detect latent or old blood

1894 history

Pitoroski wrote the earliest reference to blood spatter

Splashes shaped like exclamation points

Shape and position of spatter pattern can help locate the position of the victim at the time of the attack

Angle of impact

The angle at which a blood droplet strikes a surface

What chemicals must investigators spray to detect blood that may be visible?

The area must be sprayed with luminol which reacts to hemoglobin found in red blood cells chemical produces light for approximately 30 seconds.

How does one determine the "area of origin"/

The area of origin is th elocation of the blood source as viewed in three dimensions. It is determined by projecting angles of impact of individual bloodstains.

When blood falls on a flat surface

The blood drop will have a curved surface, the blood drop does not totally flattened out, cohesion sticking together, surface is elastic giving the top of the blood spatter a spherical shape

Given blood spatter patterns it is possible to determine

The direction blood was traveling, angle of impact, point of origin of the blood, manner of death based on velocity.

How does the shape of an individual drop of blood provide clues to the directionality of the blood?

The direction of blood is easily determined since the pointed or elongated end of the blood indicates the direction of travel.

Parent drop

The droplet from which a satellites better originates

Surface tension

The elastic like property of the surface of the liquid that makes it tend to contract, caused by the forces of attraction between the molecules of a liquid,-formation of sphere

Origin or source

The place where the blood spatter came from or originated

Spines

The pointed edges of a stain that radiate out from the spot it can help determine the direction from which the blood traveled

What is the relationship between blood velocity and spatter size ?

The relationship between them is that the blood spatter size and velocity is caused by a weapon or an injury such as beating, stabbing and gunshot wounds.

what is relationship between eyewitness and blood spatter ?

The relationship between these two is that a specific detailed story can be proven of a specific incident that as occured.

What is the ELISA test?

The test involves an antibody-protein reaction. This test is similar to one used in blood typing but uses different antibodies.

3 functions of the blood

Transport:Protection:Regulation.

What can a investigator learn from the analysis of a blood spatter

Type and velocity of the weapon. Number of Blows. Handedness R or L. Position and movement of the victim and assailant during and after. Which wound were inflicted first. Type of injuries. How long ago the crime was committed. Whether death was immediate or delayed

Arterial sports or gushes

Typically found on the walls or ceilings caused by pumping action of the heart

In what type of blood cell will we find nuclei?

White blood cells are the only blood components that have nuclei.

Invention in 1650 that dealt with blood:

William Harvey was an english physician who made seminal contributions in anatomy he was the first know physician to describe the properties of blood being pumped to the brain and body by the heart.

What type of tissue is blood ? what are the main components of blood?

blood is circulating of 3 components: red blood cells, white blood cells,and platelets and plasma ,plasma carries antibodies, hormones clotting factors nutrients and minerals throughout the body.

History of Blood spatter

in 1895, Edward Piotrowski wrote the earliest reference to blood spatter analysis. In 1939, Dr.Victor Baltnazard was the first researcher to analyze the meaning of blood spatter pattern. In 1955 blood spatter evidence used by the defense in the sam shepard case helped to exonerate him. In 1971 investigators began to use the physics of blood spatter analysis.

what is blood spatter? what is the significance in forensic science ?

in 1971, investigators began to use the physics of blood spatter analysis as a tool in modern forensics examiner today, blood spatter evidence is an integral part of crime scene analysis.

What can we determine from blood spatter evidence?

using blood spatter evidence can determine the area of origin of the blood, the direction the drug was traveling and the angle of impact.

why do blood droplets have shape?

when blood comes in contact with aanother surface the blod tends to adhere to the surface. As a result less blood continues to move and to point of impact, the blood droplets are wider than the forward travelling edge of the blood.

what are antibodies?

white blood cells secret proteins known as antibodies which assist in the immune response by labeling foreign materials