Blood Splatter Patterns

Not every result of Blood Splatter Pattern will qualify as incontrovertible evidence, but the following are some things a bloodstain pattern analyst may be able to determine conclusively and state as fact:

Movement and direction of persons or objects while they were shedding blood.

  • Position of persons or objects during bloodshed.
  • Movement of persons or objects after bloodshed.
  • The mechanism or object used to create a specific pattern.
  • The direction a stain was traveling when it was deposited.
  • The area of origin of an impact pattern.
  • The minimum number of impacts during an incident.
  • The sequence of events.

A basic understanding of blood spatter analysis allows first responding officers and investigators alike to assist in correctly collecting and preserving bloodstain data at the scene. If they know what they have at the scene, then based on their department policy they should know what they need to do next. Bloodstain pattern analysis requires sufficient education and training to be an effective investigative technique, which not all law enforcement officers attending a crime scene will necessarily have.

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1. Draw what you would expect a drop of blood to look like if it had fallen 20cm, 60cm and 150cm

2. Define the term crenation, and explain its relationship to fall height?

3. How does the angle that blood drops affect the shape of a blood drop?

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