contact traces: blood
DESCRIPTION
Contact Traces: Blood. Contact Traces: Blood. Serology: The study of blood and other liquids in forensics. Taking a sample of blood off the car windscreen. What is Blood?. Makes up 9% of a person’s body weight. T he average adult has about 5 to 6 litres of blood in their body. - PowerPoint PPT PresentationTRANSCRIPT
Contact Traces: Blood
Contact Traces: Blood
• Serology: The study of blood and other liquids in forensics.
Taking a sample of blood off the car windscreen
What is Blood?• Makes up 9% of a person’s body weight.• The average adult has about 5 to 6 litres of
blood in their body.
Blood and Crime• Common evidence in violent crimes
What kind of violence would lead to blood traces?
http://www.staffs.ac.uk/schools/sciences/forensic/forensicfacilities/photography.jpg
Blood and Crime• Difficult to remove from a crime scene which
makes it very incriminating evidence
Blood and Crime• Tests for blood are so sensitive that they can show
up blood that isn’t visible to the eye.
A trail of latent blood made visible with the use of a reagent called luminol
Blood Groups• Discovered by Karl
Lansteiner in 1901.• Four blood groups
How is this useful in forensic science?
Blood Groups• Percentage of ABO blood group types in
Australia10%
38%49%
3%
B
A
O
AB
Blood Groups• Further categorized based on another antigen
discovered by Dr Landsteiner in 1927.
Blood Groups• Blood groups are inherited from your parents• Only the dominant group is expressed
A O
B
O
Blood Spatter: Prac this week• Examination of blood splashes and smears at a
crime scene tell a story (click below for video)
Blood splatter analysis
Dexter (click below for video)exterDe
Bloodstain patterns
1. Passive Bloodstains are caused by the force of gravity
Bloodstain patterns
2. Projected Bloodstains occur when some sort of energy or force has been transferred to the blood source.
Bloodstain patterns
3. Transfer/Contact bloodstains occur when a bloody object comes into contact with another object.
Blood splatter analysis
• http://www.youtube.com/watch?v=2UV_moaF45I
Determining Angle of Impact
DNA: Deoxyribonucleic Acid