Chapter 11 Study Guide

Created by: Meghan Meyer

BPA: Bloodstain Pattern Analysis

What can blood spatter tell an investigator?

  • Type of velocity and weapon
  • Number of blows
  • Whether suspect was left or right handed
  • Position of movements during and after attack
  • Type of injuries
  • How long ago crime was committed
  • Whether death was immediate or delayed

How is blood detected at a crime scene?

  • Light Source: High intensity lights or UV rays
  • Blood Reagent Test: Presumptive tests used at scene to detect hemoglobin
  • Luminol: Helps to find traces of blood if it has been cleaned or removed
  • Fluorescence: Helpful in detecting latent or old blood
  • LCV (Leuco Crystal Violet): Used to enhance the blood


  • Spatter: Blood stains created from the application of force
  • Origin/Source: Where the blood spatter came from
  • Angle of impact: The angle at which blood strikes a surface
  • Parent drop: Where the satellite drop originate from (big droplet)
  • Satellite Spatters: Small drops of blood that come from parent droplet
  • Spines: Pointed edge of stain that radiate from spatter

Blood Stain Patterns

Passive: Created because of gravity, series of drops or blood pools

Projected: Occur when force is applied to the source of blood (low, medium or high impact)

Transfer or Contact: When a wet/bloody object comes in contact with a target surface

What is blood?

Formed elements and plasma.

Erythrocytes (red blood cells)

Leukocytes (white blood cells)

O + - Considered universal donor because it can be given to anyone, regardless of blood type

A + -

B + -

AB + - Considered universal receiver because it can accept blood from anyone, regardless of blood type