Bloodstains are Like Behaviors: How Analyzing Blood Can Help You Analyze Behavior

Bloodstains are curious little things. I became fascinated with bloodstains in graduate school in 2002-2003. Of course me being me, my neighbors thought I was nuts as I slung beet juice from various weapons: knives, tools, 2x4s out in the yard. Lucky for me I made contact with “The Father of Bloodstain Pattern Analysis”, Dr. Herbert Leon MacDonell who was known for many things, but for me, he was a teacher. I attended his Bloodstain Evidence Institute in May 2003. He invited me to intern with him, so I did for 100+hours. Then he told me I understood the subject well and offered me a job. It was then I landed my first “forensics” job analyzing bloodstains for Dr. MacDonell. He trained me to reconstruct crime scenes. He trained me to read blood like you’re reading these letters that spell words. He taught me to teach bloodstains. He trained me to conduct research and work cases he took in at his private lab. I was very lucky to have him invest in my education and for him teaching me, I will be always be grateful.

A few bloodstains don’t make a pattern. What does that mean? I means if you see one, two, or three bloodstains in a group, it is not a pattern. It is a few bloodstains. In order to qualify bloodstains as a pattern, the distribution must meet certain criteria. First they must be similar in size. Second they must be similar in shape. Third, they must follow some kind of sequence from an event. Fourth, they must be located in one place. And that’s for starters. Imagine on a wall you have 100 little bloodstains distributed horizontally across a few feet. You notice the majority of them look to be about the same size and shape. That’s a bloodstain pattern. Size, shape, quantity…all required components.

Interestingly, understanding bloodstain pattern analysis can help you understand criminal behavior too. Of course, learning bloodstain pattern analysis can help you understand offender behavior pursuant to how someone injures or kills another person, but that’s not where I’m going with this today… Bloodstain patterns and behavioral patterns are similar. Bloodstain patterns and behavioral patterns both require a repeated sequence reflective of an event. Both require quantity. Both require components have similar characteristics.

For example, domestic violence could be defined super simplistically as a pervasive pattern of coercive controlling behaviors for the purpose of abuse. Behaviors include physical assault, sexual assault, name calling, belittling, stalking, financial control. These are behaviors that in part or in totality can be part of the pattern of domestic violence. So when you see one behavior…belittling for example, that is not in and of itself a pattern. But when an offender is belittling, physically assaulting, emotionally abusing, and controlling his or her victim financially that is a pervasive pattern of domestic violence abuse.

Let’s look at killers. When an offender beats to death in the head his or her victim with a club, very likely is it we will find a distributions of bloodstains from the various impacts to the head both independent and overlapping with one another. The bloodstains size will be reflective of the weapon’s velocity at the point of impact. The blood will spatter only after the initial injury is made then impacted again by the weapon spattering blood that’s pooled or is bleeding from the injury. From the bloodstain patterns, we can tell the attack was a beating, we can determine where the victim was bleeding in the scene during and after the attack, we might be able to figure out how high above the floor or ground the victim was, and how close to certain objects the victim was. Bloodstain pattern analysis from this perspective tells us a lot about the how the killer killed. Now think of one distribution. Each bloodstain is a behavior. The behaviors are clustered in one area. They all look have similar characteristics.

When applied to killers and rapists, the word serial could mean in part, repeatedly committing the same crime where similar characteristics foreshadow predictable behavioral patterns. Conversationally, speaking, serial killers are offenders who kill more than one person on more than one occasion. And serial rapists are offenders who rape more than one victim on more than one occasion. So like groups of bloodstains with similar characteristics making bloodstain patterns, groups of homicidal behaviors and sexual assault behaviors with similar characteristics make behavioral patterns of serial criminal acts.

Stalking could be defined as a a willful, malicious, repetitive pattern of behavior that includes following or harassing another person in person or online for no legitimate purpose and for the serial stalker, bloodstains are like behaviors too. Serial killers and serial rapists exhibit similar characteristics like choosing their targets, managing logistics to create an opportunity to offend, bringing weapons to and from the crime scene, objectifying their victims, or depersonalizing their victims just to name a few. Serial killers and rapists might have personality disorders, but many are not psychotic contrary to popular belief…and the same with serial stalkers. Serial stalkers are many times motivated by anger. They use stalking behaviors to manage their anger and hostility towards their victims. Like serial killers and rapists, serial stalkers are chronic. This means they have more than one victim over time.

And what about a series of burglaries that all happen in the same neighborhood, around the same time of day or night, using the same point of entry on all locations, where the same kind of items are stolen from each home. Serial burglars aim to gain property to meet their needs. And just like serial killers, rapists, and stalkers,, serial burglars can plan their crimes or commit crimes of opportunity, choose their targets based on consistent criteria, and mitigate the logistics of their offenses with anti-forensic measures.

Bloodstains are like behaviors. One bloodstain is like one behavior. Alone, one bloodstain might not tell you a whole lot. But when present among a group, one bloodstain can sometimes be the difference between murder and manslaughter…I know because I’ve seen it happen in the courtroom. We had a defendant who beat a woman to death with a shovel in her front yard. One bloodstain was the difference between life and death for this guy. He ended up taking a plea to 40 years or close to it if I remember correctly. Had he gone to trial, the bloodstain on the aluminum siding about two feet above the ground showed that as the woman blindly crawled across the yard trying to get to the front door of her house, she passed the door and kept crawling at which point he delivered the final blow beyond the point of the door where she was found by her husband a few hours later.

So the next time you are trying to make heads or tails of individual behaviors you’re seeing in a subject, think of how they might link together by “size,” “shape,”, and quantity. Do you have a pattern? A few bloodstains don’t make a pattern. And a few behaviors don’t make a pattern. But learning how bloodstains meet the requirements for becoming a pattern can help train your brain to learn to identify and classify behaviors that give rise to establishing a pattern of behavior that repeats in sequence, quantity, characteristics, and location.