Bloodstain Patterns

Identification, Interpretation and Application

Anita Y. Wonder

• Publisher: Academic Press
• Year: 2015
• Print ISBN: 9780124159303
• eBook ISBN: 9780124159655
• Topic: Law
• Subtopic: Forensic Science
• Index: Law

Bloodstain Patterns: Identification, Interpretation and Application combines material from Blood Dynamics (2001) and Bloodstain Pattern Evidence (2007) with updated case work and scientific advances from medical and hard sciences. The text expands coverage of such areas as arterial damage pattern identification, staging of crime scenes, legal applications and problems from both sides of the bench, and extending teaching and training to those outside criminal justice. With violent offenders more aware of crime scene investigation techniques and attempting to frame others, the text expands outdated basic training programs that are insufficient to identify attempts to confuse the investigation. This book clarifies previous understandings as well as bridges the gap toward future advance courses. Based on the work of Paul Leland Kirk, the book's focus is on first line investigators' accuracy in identifying specific bloodstain patterns, correctly interpreting and applying them to casework. - Combines and updates material from Blood Dynamics and Bloodstain Pattern Evidence into one comprehensive reference - Covers new topics, including arterial damage pattern identification, staging of crime scenes, legal applications, and problems from both sides of the bench - More than 300 full color photographs, some with line overlays showing the objective criteria which identify patterns

Section II

Identification

Outline

Chapter 4. Review of Historical Approaches to Bloodstain Pattern Identification

Chapter 5. Differentiations Between Similar Patterns

Chapter 6. How Many Pieces of Evidence?

Chapter 4

Review of Historical Approaches to Bloodstain Pattern Identification

Abstract

Back in the late 1960s, Dr. Paul L. Kirk gave presentations before the annual California Trial Lawyers Meetings in San Francisco. He kept notes of his lectures, which, after his death in 1970, were stored at the University of California, Berkeley, Bancroft Library. What he favored for the future of bloodstain pattern evidence was described in at least one lecture. His concept remains true to scientific logic and needs no improvement. The identification guidelines included in Blood Dynamics and reiterated in Bloodstain Pattern Evidence, Objective Approaches and Case Applications emphasized Dr. Kirk’s concept of bloodstain pattern evidence. After his death in July 1970, attitudes toward the evidence shifted toward a path that Dr. Kirk appeared to discourage with his lectures before trial lawyers, specifically where expert witnesses claimed opinions solely based on their experience, which may not be supported with science-based information.

Keywords

dynamics identification; whole pattern; direction of travel; alignment; distribution; density; bloodstain pattern interpretation

Back in the late 1960s, Dr. Paul L. Kirk presented the “Identification of Bloodstain Dynamics” to the annual California Trial Lawyers Meeting in San Francisco. His notes on historical precedents are available for review at the University of California, Berkeley, Bancroft Library. What was to be an outline for identifications, interpretations, and applications of bloodstain pattern evidence was presented in the lecture quoted here:

Distribution and Character of Blood Spots

One other type of information [from physical evidence] that is most helpful and greatly neglected is the analysis of blood distribution at the scene of violent crime. The Hydrodynamics [sic] of flying blood drops has received very little attention, although numerous discussions of angle and velocity of single drops are available. The general pattern is actually far more informative, and in favorable cases, is by far the most significant of both the assailant and the victim during the critical moments of the commission of the crime.

Blood which is thrown during a crime shows definite regularities as to size and velocity, which will differ depending on whether they received their velocity from impact, from being thrown from a bloody weapon as it swings, or from spurting from a severed artery. These patterns are not only different, but show characteristic patterns that can often be recognized. Disregard of this rather obvious source of information has lessened the total information obtained by investigators of many serious crimes and is well worthy of more study and of greatly increased utilizations as an investigative function. It is expected that rather lengthy experiments already conducted in this area of research will reach the stage of publication shortly (Paul Kirk Papers).

The identification guidelines included in Blood Dynamics and reiterated in Bloodstain Pattern Evidence, Objective Approaches and Case Applications emphasized Dr. Kirk’s concept of bloodstain pattern evidence. After his death in July 1970, attitudes toward the evidence shifted in a direction that was contrary to what was advocated in his notes and lectures. This included not accepting, specifically, expert witnesses who might claim opinions soley based on their experience. Dr. Kirk’s papers suggest he was very academically inclined, which could satisfy the demands for scientific principles of the NAS Report and NSIC (National Institute of Standards and Technology).

Identifying the dynamic act that distributed blood drops is probably the simplest step in a bloodstain pattern analysis. Unfortunately, it is that step which is sometimes skipped or assumed from information other than the alignment and distribution characteristics of the bloodstains themselves. Too often in crime scene processing, an investigator may jump from verifying a substance as blood to interpreting what the mere presence of blood spots (spatters) of certain size and shape means. Predominant size and shape of the spatters may then be used as justification for the conclusions regarding involvement and stated as consistent or inconsistent with a desired assumption. Whether impact, castoff, or arterial spurting was responsible for the group of spatters may be missed in favor of the size and angles of individual spatters lumped with an assumed relative velocity of a weapon. An example of this is to say, “That’s high velocity impact spatter,” when it is known, or assumed, that a victim sustained a gunshot injury. After this statement, conclusions are drawn that anyone with small bloodstains on his or her person was the shooter. Sadly, the case may not be that simple.

Another example is the case in which a neighbor came into an apartment because he heard moaning on the other side of the door. The badly injured victim was still alive and wheezing while propped against the door. The neighbor raised the victim’s head and received respiratory-distributed blood spatters on his shirt. The responding law enforcement officer arrested the neighbor and claimed that the “suspect had medium velocity impact spatters on his shirt, which meant he did the beating.” The facts were that the victim, beaten with a cricket bat found at the scene, lived for a period of time after the assault. The neighbor was just attempting to aid the victim and had fine spatters near the shoulder where the victim’s head rested. By virtue of spatter size, the conclusion should have been high velocity impact spatter, but no gunshot was involved. No one else was even considered, despite evidence that the assailant walked, dripping the victim’s blood, to a sink and washed up before leaving the scene. The neighbor showed no evidence of attempts to wash up and no connection to the blood drips leading to the sink before the police arrived.

An occurrence that is worse than misinterpretations made during investigation may happen if bloodstain pattern analysis is not considered until after an arrest is made, when the case is being prepared for trial against a specific accused. In this case, bloodstain patterns are not used in the investigation but rather brought in later to prove a specific point. Although one hopes these occurrences are rare, in some jurisdictions, a prosecutor may ask the crime lab to supply evidence against a specific suspect while ignoring exculpatory interpretations of the patterns identified. If bloodstains exist at a crime scene, confirmation information that may be vital to an investigation is available and free for the taking so that resulting charges are reliable and accurate, even if, or especially if, staging and contamination occurred. To ignore, or to use it only if other evidence is unavailable, i.e., as “instant evidence,” is to not fully appreciate the probative benefits of this form of forensic evidence. The result could also be a waste of time, money, and possibly the quality of human lives. Though seldom acknowledged, embarrassment may result during trial if the opposing counsel puts on a better trained, more objective bloodstain pattern analyst (Reynolds, 2012).

It has been repeatedly emphasized that size and shape alone cannot be used to identify the dynamics that distributed blood drops fo...

Table of contents

• Cover image
• Title page
• Table of Contents
• Dedication
• Copyright
• Acknowledgments
• About the Author
• List of Figures
• Section I. Introduction
• Section II. Identification
• Section III. Interpretation
• Section IV. Application
• Section V. Research for the Future
• Index