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Bloodstain Patterns

A Preliminary Validation of the Use of 3D Scanning for Bloodstain Pattern Analysis

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Abstract

3D scanning technology is beginning to be used more commonly to record crime scenes. Besides being able to document the scene and the locations of evidence within it, 3D scanners and associated software can now be used to analyze impact bloodstain patterns. In the present study, two “doubleblow” impact patterns were created in a classroom setting for analysis using both the HemoSpat bloodstain pattern analysis software and the FARO Focus3D scanner with FARO Scene software. Both methods produced area of origin results that were acceptably close to the actual initial blood source location.

Introduction

Impact bloodstain patterns, created when a blow is struck, can sometimes be analyzed to try to determine the approximate location of the source of the blood [1]. With this information in hand, an investigator can try to determine what might have occurred at the scene of the crime. Blood source areas of origin may indicate...

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Bloodstain Patterns

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Blood spatter patters, at the scene of a violent crime can indicate how the crime occurred. The shape of spots of blood can be used to determine an estimate of their velocity and/or impact angle and/or distance fallen. Elongated portions of the blood spatter indicates the direction that the blood drop was traveling when it impacted the surface.

Some of the variables used in blood spatter analysis are:
• Size of the blood spot
• Quantity of blood
• Shape of the blood spot
• Distribution of the blood in the crime scene
• Location of blood stains
• Angle of impact
• Texture of target surface
Blood that drips vertically from a stationary source onto a smooth, hard, flat surface is usually circular with crenated edges. Rough surfaces result in more spatter. (See Figure B-2) The shape of a bloodstain indicates its direction of travel. Such bloodstains are shaped more like an exclamation point where the shape and length indicate

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Bloodstain Pattern Analysis Involves The Scientific Study Of The Static Consequences…

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A. INTRODUCTION

Bloodstain pattern analysis involves the scientific study of the static consequences resulting from dynamic blood shedding events. A detailed study of bloodstain patterns at crime scenes often develops invaluable evidence. The distribution, size and shape of bloodstains on a victim, on a suspect, or on the walls, floors, ceilings, or on objects at the scene can help reconstruct these blood shedding events. Bloodstain pattern analysis can also help one evaluate the credibility of statements provided by a witness, a victim, or a suspect. Physical evidence waits to be detected, preserved, evaluated, and analyzed. Herb McDonnell once said that in the course of a trial, both defense attorneys and prosecuting attorneys may lie, witnesses may lie, and the defendant certainly may lie. Yes, even the judge may lie. Only the evidence never lies. But if the evidence is not properly recognized, documented, preserved, and processed, all we have are attorneys, witnesses, defendants, and judges. Enough said.

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