1. FORENSICS OF BLOOD SUNDAY ACADEMY 2011-12

2. SEROLOGY What is serology? Serology is the study of serums. Examples:
Blood
Saliva
Sweat
Etc.

3. HOW MUCH BLOOD DO WE HAVE?
You have about 10 pints of blood pumping through your body.
Plasma is the liquid portion of blood and it is 55% of the blood volume.
Red blood cells transport oxygen from the lungs and carbon dioxide to the lungs for removal.
Antigens on the surface of the RBC give them their blood characteristics.
White blood cells produce antibodies to disable and/or destroy invaders.
Platelets help to clot blood. The protein fribrin catches red blood cells.

4. BLOOD TYPING
In 1901 Karl Landsteiner discovered the human blood groups.
The difference in blood groups are due to the presence or absence of certain protein molecules called antigens and antibodies.
Blood Type
Antigen
Antibody % A B 42 10 AB
A & B
None 4 O 44
Landsteiner broke the groups into the familiar A, B, AB, and O.

5. BLOOD TYPING
Besides A, B, AB, and O there are over 100 blood factors that can be used to identify a person.
Example: RH factor
Until the 1990’s scientists used these factors to identify someone.
Today we use:
DNA

6. BLOOD AT THE CRIME SCENE
Is it blood?
We use presumptive tests to answer this question.
Hemastix – reacts with the hemoglobin in blood.
Hemastix will turn from yellow to dark green if blood is present.

7. BLOOD AT THE CRIME SCENE
Presumptive Tests (continued)
Kastle-Meyer Test
A drop of phenolphthalin reagent is added to the sample, and after a few seconds, a drop of hydrogen peroxide is applied to the swab. If the swab turns pink rapidly, it is said to test presumptive positive for blood.

8. BLOOD AT THE CRIME SCENE
Presumptive Tests (continued)
Luminol – reacts with iron present in blood and a chemical reaction that leads to luminescence revealing the location of the blood.
Picks up blood even if diluted up to 10,000 times.

9. BLOOD AT THE CRIME SCENE
From what species?
Precipitin or Gel Diffusion – Blood from mummies 4,000 – 5,000 years old still give positive results!
If it’s human blood, whose is it?
ABO Testing
DNA Fingerprinting

10. INTERPRETING BLOOD SPATTER
Blood spatter can tell us the following:
Direction blood droplet was moving
Where the blood droplet came from
Type of weapon used in the crime
Position of victim, suspects, and objects
Sequence of events

11. INTERPRETING BLOOD SPATTER
How to tell the direction that blood droplet was moving.
Here is a picture of some blood spatter which hit a surface.
The pointed part of the blood spatter give you the direction the blood was traveling at the point of impact.

12. INTERPRETING BLOOD SPATTER
Working with multiple droplets can tell were the victim was located when the crime was committed.

13. TYPES OF BLOOD SPATTER
Passive blood spatter is created by the force of gravity.
Height determines diameter of blood spatter.
Irregular spatter pattern indicate higher fall.

14. TYPES OF BLOOD SPATTER
Projected blood spatter occurs when energy has been transferred to the blood source.
Low, Medium & High Velocity
Falling blood drops
Gunshot wounds
Arterial Spurting
Cutting of an artery
Expiratory
Blood from mouth or nose

15. TYPES OF BLOOD SPATTER
Contact or Transfer blood spatter occurs when an object with blood on it comes into contact with other objects.
Wipe
Swipe

16. ANGLE OF IMPACT
The angle of impact is useful in determining where blood spatter originated from.
To find the angle of impact:
Sin (angle) = Width / Length

17. Activity One Blood Typing
In this activity, you will be testing samples of blood to determine the blood type.

18. Activity Two: Determining the Height of blood spatter
In this activity, you will make passive blood drops from specific heights, than by graphing the diameters of known blood drops, use the graph to determine the height that unknown blood drops.

19. Activity Three: Blood Spatter Patterns
In this activity, you will be spattering blood on paper and analyzing the patterns.

20. Activity Four: Angle of impact
In this activity you will be dropping blood at specific angles, calculating the angles that your spatter hit the paper, and then comparing the two.

21. Activity Five: Determining the Origin
In this activity, you will take the blood spatter sheets you made in activity two and use them to determine their origin.

22. Now its time to play with Blood