Analyzing Blood Stain Patterns in Forensic Science

Ray Ernst, an assistant professor at Hilbert College, introduces blood stain pattern analysis, focusing on how blood behaves outside the body and its cohesive properties. He demonstrates the effects of different instruments on blood spatter and explains the types of blood spatter: low, medium, and high velocity. In a simulated blood stain room, students learn to analyze blood patterns, including passive drops, transfer stains, and voids. They practice determining the area of convergence and documenting high-velocity patterns, such as those from gunshots. The course prepares students for real-world forensic investigations.

What is the primary focus of blood stain pattern analysis?

• To determine the age of the blood

• To identify the blood type

• To measure the temperature of the blood

• To understand how blood behaves outside the body

What are passive drops in blood stain analysis?

• Blood drops that fall due to gravity

• Blood drops that are sprayed from a gunshot

• Blood drops that are smeared on a surface

• Blood drops that are flung from a weapon

What can transfer stains indicate in a crime scene?

• The type of weapon used

• The presence of an object that was removed

• The time of the crime

• The direction of a person's movement

How is the area of convergence determined in medium velocity blood spatter analysis?

• By measuring the temperature of the blood

• By analyzing the color of the blood

• By tracing lines through elongated drops

• By counting the number of drops

What does a tail on a blood drop indicate?

• The height from which the blood fell

• The direction the blood drop was traveling

• The volume of the blood drop

• The speed of the blood drop

What is the role of trigonometry in blood stain pattern analysis?

• To calculate the volume of blood

• To determine the angle of impact

• To measure the temperature of the blood

• To identify the blood type

What is a characteristic of high-velocity blood spatter?

• Elongated drops with tails

• A mist-like spray

• Blood pooling on the floor

• Large, circular drops

What is cast-off in blood stain pattern analysis?

• Blood that is smeared on a surface

• Blood that is sprayed from a gunshot

• Blood that is flung from a moving weapon

• Blood that drips due to gravity

What does the presence of circular drops behind a suspect indicate?

• The suspect was injured

• The suspect was swinging a weapon

• The suspect was moving quickly

• The suspect was standing still

Why is it important not to over-interpret blood stain patterns?

• It can alter the evidence

• It can lead to incorrect conclusions in court

• It can damage the crime scene

• It can confuse the investigators