| Key Concept | Technical Details | Forensic Significance | Investigative Applications |
|---|---|---|---|
| Passive Bloodstains |
– Formed by gravity (e.g., drips, pools) – Shape depends on surface texture and angle – Size varies based on distance from source |
– Helps determine the position of the victim – Indicates time elapsed since bleeding – Provides clues about the crime scene dynamics |
– Reconstructing the sequence of events – Identifying the location of the victim – Estimating the time of injury |
| Projected Bloodstains |
– Caused by force (e.g., arterial spurts, impact spatter) – Patterns include linear, arcing, or radiating stains – Size and shape depend on force and distance |
– Indicates the type of force applied – Helps determine the weapon used – Provides information about the assailant’s position |
– Linking suspects to the crime scene – Identifying the type of weapon – Reconstructing the assault dynamics |
| Transfer Bloodstains |
– Created when a bloody object contacts a surface – Patterns include swipes, wipes, and imprints – Shape depends on the object and movement |
– Identifies objects involved in the crime – Links suspects to the scene – Provides evidence of movement or struggle |
– Identifying tools or weapons used – Tracing the movement of individuals – Confirming or refuting suspect statements |
| Impact Spatter |
– Results from force applied to a blood source – Classified as low, medium, or high velocity – Patterns include mist-like stains or larger droplets |
– Determines the type of force (e.g., blunt, sharp) – Helps reconstruct the number of blows – Indicates the direction of force |
– Identifying the weapon used – Estimating the number of blows – Determining the sequence of events |
| Cast-Off Stains |
– Created when blood is flung from a moving object – Patterns are linear or curved – Size and shape depend on the object’s motion |
– Indicates the motion of the weapon – Helps determine the number of blows – Provides information about the assailant’s position |
– Reconstructing the assault dynamics – Identifying the weapon used – Linking suspects to the crime scene |
| Expirated Bloodstains |
– Caused by blood being expelled from the mouth or nose – Patterns are often light and mist-like – May contain air bubbles or saliva |
– Indicates respiratory involvement – Helps determine the cause of injury – Provides clues about the victim’s position |
– Identifying the cause of death – Reconstructing the victim’s last moments – Confirming or refuting suspect statements |
| Void Patterns |
– Areas lacking bloodstains due to obstruction – Shape matches the obstructing object – Provides negative evidence of objects or individuals |
– Identifies objects or individuals present during the event – Helps reconstruct the crime scene – Provides clues about the sequence of events |
– Identifying missing objects or individuals – Reconstructing the crime scene layout – Confirming or refuting suspect statements |
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