Abstract
Blood Pattern Analysis (BPA) is an important component of crime scene investigation when an act of wounding has taken place. In the case of a trial, the evidence collected through BPA can be useful to confirm guilt or vindicate the defendant. The instant essay delves into the science and practice of BPA including a Christina worldview component. It also addresses the level of training, expertise, and tools necessary to effectively undertake BPA duties and present evidence in court.
Technical Elements
Bloodstain Pattern Analysis (BPA) is the science of evaluating and studying stains of blood in a crime scene. BPA involves establishing if any of the substances in the scene of crime amounts to blood, and establishing where the blood could have come from. BPA experts seek to understand what the blood indicates about the events that took place in the crime scene. Technical aspects of BPA include pattern diversity principle, the principle of stain shape and vector correlation and the physically altered bloodstain (PAB) principle (Textbook).
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BPA Methodology
The methodology of Blood Stain Analysis combines four main components. The first is the size of the bloodstains which can show how much blood was shed at the scene and the distance between the surface of the stain and the act of wounding (Textbook). The second is the shape of the bloodstain, which can reflect of there was enough blood for gravity to act on it if there were splattering and the nature of wounding. The third is the distribution patters of the blood, which would reflect the activities during and after the act of wounding. Finally, there is the interrelationship between the different stains in the crime scene (Attinger et al., 2019). The BPA expert seeks to combine the elements above to recreate the scene that caused the bloodstain.
Examples of Blood Stains at Crime Scenes
There are two main types of blood in crime scenes, liquid, and dried blood. Bloodstains mainly involve dried blood smeared upon surfaces at or near the crime scene (Attinger et al., 2019). Examples include bloodstain droplets on walls, bloodstains smeared onto weapons used in the crime or bloodstains on the floor where a wounded person passed through.
Discuss Detection and Documentation of Bloodstains
The detection of bloodstains can be visual for large visible blood stains or through the use of chemicals for stains not visible to the naked eye. Modern bloodstain detection uses chemicals such as luminol, leuco-crystal violet (LCV), fluorescein, and amido-black (Textbook). These chemicals react with the specific chemicals within the blood such as iron to produce a glow that is visible under colored light. The documentation of bloodstains requires the inference of an expert who uses a set of instruments. Among the necessary instruments include measuring equipment such as ruler and protractors, and calculating equipment to assist in analyzing the data form the measurements (Textbook). Photography and video are also important for the preservation of data for further analysis and where applicable, eventual testimony in court.
Expert Court Testimony
As determined in Daubert v. Merrell Dow Pharmaceuticals, Inc., there are four main components of expert testimony, all of which are applicable n blood pattern analysis testimonies. First is the testing. The expert needs to provide evidence of having the ability to conduct tests and having conducted those tests at the crime scene ( Kumho Tire Co. v. Carmichael ). The second is acceptability. The expert should convince the court that the methodology and procedure used in analyzing the blood patterns are acceptable in the BPA field. The third is peer-review which involves evidence that another expert, faced with the same scenario would arrive at the same conclusion as the expert witness. Finally, the expert witness should provide the failure rate of the method used as no method is foolproof. Professional training is necessary for expert testimony in BPA.
The necessity of BPA Capability
BPA evidence leads to the establishment of criminal or civil liabilities in cases where wounding or even fatalities have occurred in a crime scene. Under such circumstances, errors can amount to monumental injustices (Attinger et al., 2019). To avoid erosion of justice, a high level of expertise is necessary for BPA analysis and the eventual testimony in court.
Conclusion
It is evident from the above that Blood Pattern Analysis (BPA) is both a complex and important component of crime scene investigation. A high level of expertise and specialized tools are necessary to effectively analyze a crime scene. A BPA expert can recreate a crime scene and inform the court on what happened, thus either vindicating or confirming the guild of the defendant. From a Christian worldview perspective, God says in Isaiah 61:8 “For I, the LORD, love justice; I hate robbery……”. God is interested in justice and BPA seeks to ensure justice for victims of crimes. BPA thus aligns with the Christian World View.
Conclusion and Recommendations
A high level of expertise if necessary in BPA and testimony.
Testimony should include evidence of testing.
Testing includes the use of chemicals to identify blood patterns invisible to the naked eye.
Witnesses should use acceptable standards and procedures.
Evaluation tools and appliances are invaluable.
Witnesses should provide peer-review for the conclusions arrived at after BPA.
Evidence of error rates is also necessary to guide the court on the reliability of the evidence adduced.
An understanding of anatomy is important in BPA as it also involves the evaluation of wounding.
BPA experts should keep a proper record of evidence from crime scenes.
Avoidance of bias and prejudices is critical to the acceptable expert witness as justice and fairness is an important component of the Christian world view.
BPA evidence can have major implications in criminal trials and should always be handled professionally. Giving false witness is a sin under the Christian World View.
References
Attinger, D., Liu, Y., Faflak, R., Rao, Y., Struttman, B. A., De Brabanter, K., ... & Yarin, A. L. (2019). A data set of bloodstain patterns for teaching and research in bloodstain pattern analysis: Gunshot backspatters. Data in brief , 22 , 269-278.
Kumho Tire Co. v. Carmichael , 526 U.S. 137, 119 S. Ct. 1167, 143 L. Ed. 2d 238 (1999).
