Blood AnalysisForensic Science 4/2/14

True or False – correct if False◦ ABO blood types are considered individual

evidence.◦ Serology is the study of blood.◦ The precipitin test is used to determine if a red

stain is blood.◦ Blood spatter is caused by a blood source coming

in direct contact with an object. HW:

◦ Study for Blood Quiz (on the Blood Basics notes and ABO genetics)

◦ Blood Species Questions (if needed—probably not)

Drill

IWBAT◦ Determine the ABO genetics for different

parent/child combinations.◦ Identify similarities and differences between

different blood species.

Objectives

Drill Finish Notes Blood Species Questions ABO Genetics WS Closure

Agenda

Forensic Science: Fundamentals & Investigations, Chapter 8

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Blood Splatter Analysis —Directionality

The shape of an individual drop of blood provides clues to the direction from where the blood originated. How will the point of impact compare with the rest of a blood pattern?

Determining direction of travel

Determining angle of impact

http://www.howstuffworks.com/bloodstain-pattern-analysis3.htm

width

length

Determining the source

Forensic Science: Fundamentals & Investigations, Chapter 8

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Blood Splatter Analysis

Lines of convergence—two or blood splatters can pinpoint the location of the blood source

Determining the source

Area of convergence

Forensic Science: Fundamentals & Investigations, Chapter 8

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Blood Splatter Analysis—Six Patterns

Describe each of these: a) Passive drops b) Arterial gushes c) Splashes d) Smears e) Trails f) Pools

Forensic Science: Fundamentals & Investigations, Chapter 8

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Blood Splatter Analysis—Impact

Patterns can help investigators determine the type of weapon used

What kind of a pattern is produced by a gun shot?

What kind of a pattern is produced by a hammer blow?

Forensic Science: Fundamentals & Investigations, Chapter 8

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Crime Scene Investigation of Blood 1. Search for blood evidence 2. Determine

a. Is the evidence blood?b. Is the blood human?c. What is the blood type?

3. Interpret the findings: a. Does the blood type match a suspect’s blood?b. If not, exclude that suspectc. If yes, decide if DNA profiling is necessary

Mammal The Bloodmobile Both by They Might Be Giants

Blood related songs

Find the sketches you made of the various species of animal blood. Answer the questions on a sheet of notebook paper.◦ Chicken blood = Bird blood

When done, pick up the ABO Genetics practice worksheet

We will review both in 15 minutes.

Species QuestionsABO Genetics Practice

Write a series of characteristics to differentiate between mammal and non-mammal blood.

Closure