Potential & Kinetic Energy:
It is important to calculate the amount of energy needed to cause specific wounds on a body. This requires an understanding of potential and kinetic energies, having to do with the laws of thermodynamics. Potential energy has to do with the position of one object to another. Suppose you pull a rubber band back in order to strike you sister on the arm. You have created the possibility of energy once you let go of the rubber band. Kinetic energy is proportional to the velocity and mass of an object when it impacts on another. The energy is measured in Joules. This happens when the rubber band is let go and it impacts from a certain distance on your sister’s arm. Scientifically, the sound you hear from your sister is the result of her pain and frustration with you :)
It doesn’t happen often, but sometimes death scenes are staged. This occurs when the perpetrator wants you to believe a certain thing happened at the scene. They rearrange the evidence to lead suspicion away from themselves or even try to change the actual manner in which the person died. It could be hanging a person after they have been killed to make it look like a suicide or fake an illegal entry into a home to make one believe that an intruder caused the death, rather than someone from inside the home. The key to not being deceived by a staged scene is good scene documentation. The most valuable tool in documentation is photography. Overall, medium range and close up photographs preserve a scene in time. Even years later clues to staging can be found from the good work of the original CSI team. Detecting staging is the process of studying patterns. Many times those that stage try too hard and the look of randomizing events give way to overt patterns that one can tell are trying to lead the investigators to one conclusion. Staging a scene indicates a certain amount of premeditation and planning. This is important in building the profile of the suspect.
Just like the name implies, marks made by weapons or tools can tell us a lot. One example is a patterned wound on a body. A convex tool or weapon, like a tire iron or round rod will many times leave two parallel red lines on the body. This is because when the tool hits the body, the blood in the skin is pushed out to the side of the tool at impact. The center of the impact is blanched due to the loss of the blood in the area of impact. Tool marks on doors, furniture and other objects can lead to a particular classification of tool or may under a comparative microscope individualize the exact tool used by wear marks.
The general definition of the term is the study of the process of fossilization and body decay. I have spent multiple weeks down in Knoxville, Tennessee at the University of Tennessee “Body Farm,” a project started by a Dr. William M. Bass in conjunction with several cooperating medical examiners offices. The purpose of the farm is to examine the process of human body decomposition from a forensic investigative point of view. Today there are six such facilities in the United States and they have given forensic investigators, physical anthropologist and medical legal investigators invaluable information concerning the various hallmarks of decomposition including time lines, methods of documentation and the process of recovery for evidentiary purposes. Taphonomy is now one of the major fields of study in death investigation and human identification.
I know this may seem gross but it is necessary to understand artifacts that are postmortem and those that are perimortem. Postmortem refers to that which occurs after death and perimortem refers to that which occurs at or near the time of death. Many new to the field of death investigation will see liquid coming out of the mouth and nose of a decomposing body, and mistake it for perimortem trauma. However, the liquid is the result of a breakdown of tissue, being pushed out of the opening of the body due to the buildup of gasses. Close examination at the lab is the best way to categorize true trauma to the body.
Sometimes individuals get confused as to why investigators go in one direction or another at the beginning of an investigation. Inductive reasoning is generally used in the beginning of an investigation because given the data at the scene we first check on the most probable hypothesis as to what happened and who may be the suspect. For example: data shows that most serial killers are Caucasian males. So if the police have multiple suspects in a serial killing, they may look at the male Caucasian suspects first. The important point in using inductive reasoning is that one must remember to clearly distinguish between what is a probability and what is a fact.
These are most commonly seen in suicide or torture cases. The tool is most often a sharp object like a knife. They are superficial cuts to the skin, never intending to cause death but rather pain. Where the hesitation marks are can tell you much about whether they were self-inflicted or done for torture or control.
Knife Wound Analysis:
A good medical legal investigator has to know not only the anatomy of the body but also the anatomy of a knife. Most knives have a sharp edge and then on the opposite side a flat, non cutting edge called a spine. This is a single edged knife. Some knives are actually “daggers” and have sharp edges on both sides. Some knives have a “quillion” or “hilt” just before the handle of the knife. Each part of a knife’s anatomy can tell us the angle of attack, the length of the blade, the design of the blade or the shape of the hilt. Having a working knowledge of knives and understanding pattern wounds on the body can tell you much about the knife and the perpetrator.
A badly burned body is typically found in this position which is characterized by bent elbows, knees, hip and neck, with the hands clutched into a fist. This is because the fire affects the tissues and muscles in certain ways, shortening and stiffening them. The body has many different tissues, each with a different structure and density. Tendons, muscles, skin, bone are destroyed by fire at different rates. Because of this phenomenon a body that has been in a fire leaves certain artifacts. One of the first tasks of a medical legal investigator is to distinguish between peri-mortem trauma and fire-related artifacts.
In a fire death may times the epidermis of the fingers separates from the inner layers of the skin. The fire causes this condition but in some cases does not incinerate the hand because of position or some other reason. A pathologist or investigator can excise this outer layer of skin and place it on their own gloved finger of thumb and get very good thumb or fingerprints. This process is also often used in drowning case for identification purposes.
A commercial cremation chamber is similar to a large pizza oven. The walls of the oven are brick-lined and the chamber can be heated up to approximately 1800-2000 degrees Fahrenheit. Because of EPA requirements there is a second lower chamber that incinerates the smoke from the first chamber. This process makes the smoke coming out of the chamber much cleaner. It can take several hours for the process and the cooling of the remaining ashes. Then remaining bone and ash is then sent through a “cremulator” which crushes any larger ash into a fine powder. In Pennsylvania and other states cremation permission must be given by the Coroner or the Medical Examiner for this process to take place. This is because there is little evidence left from commercially cremated remains.
Incident Command System:
In this age of terrorism and mass casualties there is more and more usage of a system to organize large crime scenes and mass disasters. It is called the “Incident Command System.” Large scenes require communication and cooperation between multiple organizations and government authorities. There has to be a central command that can serve as the hub for the purpose of safety, information and liaison. The command center also coordinates operations, planning and finances. If you think this sounds like setting up a corporation for one incident you are correct. Attached is a website with a good overview of the Incident Command System: https://www.osha.gov/SLTC/etools/ics/what_is_ics.html
Physical Anthropology: There are 206 bones in the human body. The study of these bones and what they can tell us about an individual is the study of forensic physical anthropology. It is a field that fascinates me and is one I have to be familiar with because of the many times I have to do shallow grave recovery. I am not an expert in every field but I must have a working understanding of each to know when and how they should be utilized in medical legal death investigation. Bones can give us an abundance of information such as:
The field of physical anthropology goes well beyond these forensic applications into the study of man’s ancestral history and the progression of other hominin ancestors. In most cases, forensics draws an anthropologist from academia or museum staff. This is because most coroner/medical examiner systems do not have enough cases to justify a full time anthropologist. This is an important fact if you are thinking of this field of forensics.
This is the study of the unique characteristics in the structure and development of an individual’s teeth. The vast majority of forensic identification is done by the study of peri-mortem dental records with post-mortem studies. Obviously the most useful part of dental records is dental x-rays but written dental records also contain valuable information that can lead to identification of a person. The formation and wear of our teeth is totally unique. We generally have 32 teeth and four sides to each tooth, so that is 128 aspects of individuality that can be compared. There are also multiple interventions of dental care such as amalgams, tooth extractions and appliances that can also be compared. There are multiple reasons for dental identification beyond criminal identification. Here is a good website to get more information: http://www.dentalcare.com/en-US/dental-education/continuing-education/ce401/ce401.aspx?ModuleName=coursecontent&PartID=2&SectionID=-1
During the investigation, I discovered a plant growing through the eye socket of of a skull. It was a macabre picture, but to me it was evidence that could give me a timeline as to when the person had been killed and buried. Many items can give you timelines: hair growth, half-life of medicines, mail on a doorstep, degradation of clothing. The plant I examined at the scene had to be collected, classified, studied and the growth rate duplicated. I needed a growth rate with a timeline estimation done by experimentation with the same species of plant. There are forensic botanists who can provide estimations of how long ago the body was buried. Botanists can also look at what is called vegetation of opportunity, which can help locate clandestine graves. This is a differentiation in vegetation from the surrounding area caused by the disturbance of the earth in the process of digging the grave.
I am often asked if a person was alive during the fire. It is a fairly simple question to answer in most cases, using deductive reasoning, which goes something like this: A human is a mammal. Mammals need to breathe to live. Humans breathe through the nose and mouth down into the bronchi of the lungs. Fires produce particulates in the air. When one breathes the particulates, there is sooting around the nose and mouth into the lungs. Therefore I can say yes the individual was alive during the fire, if that sooting is present. This is a process of top down thinking. It is based on a premise known to be true, leading towards a conclusion that must also be true. If you read the premise above, it can lead to only the one conclusion.
There is a certain amount of carbon monoxide in the atmosphere, somewhere between 0.05 to 5 parts per million. In our blood systems there is a cell whose purpose is to carry oxygen throughout the body. This cell is called hemoglobin or the red blood cell. Carbon monoxide has a better than 200 times greater affinity than oxygen to latch on to a red blood cell thus depriving the body of oxygen. This combination of carboxyhemoglobin is the percentage measurement of how many red blood cells have been replaced with carbon, depriving oxygen to the cells in the brain and throughout the body. Normal levels of carboxyhemoglobin are between five and for heavy smokers up to twelve percent. There are many factors that would indicate how quickly a person would be affected and die when over these limits. Carboxyhemoglobin is a necessary piece of evidence in any fire death.
The Merriam-Webster Dictionary defines it as “a substance used to accelerate a process (as in the spreading of fire).” The most common accelerants appreciated in fire investigations are volatile organic compounds such a gasoline, kerosene, lighter fluid or other combustible liquids. One might ask, how does one know that accelerants were used? In many cases investigators use a dog specially trained to detect multiple types of accelerants. Fire investigators study fire first by looking at patterns. They are trained to find the origin of the fire, calculate the heat of the fire and determine how it spread. They also collect samples at the point of origin and test for accelerants.
Behavior Evidence Profiling:
Evidence is first recognized, documented, collected and then processed, usually by identification teams, made up of crime scene investigators. The next step, usually done by detectives, is investigative work, which compiles all the evidence and asks the question “why.” Why is the body in that position? Why are the casings in the other room? Why was there no forced entry? This is the reconstruction phase of the process. It is not enough to have the evidence. The meaning must be decoded. It is in the reconstruction process where the final picture develops and the scene and the body start to tell their story.
Patterns are important on all phases of the investigation but a medical legal investigator is mainly concerned with those wounds on or about the body. Sometimes the absence of certain types of wounds tell you as much as their presence. In the Ewalt case it was the absence of defense wounds and the lethalness of her two wounds that told me this was most likely an experienced killer. Her wound patterns were not consistent with most domestic or passion killings. The pattern wounds on the victim’s body many times tell the intent and purpose of the killer.
My work at the scene starts at the body and works outward towards the edges of the infamous yellow tape. I first look at body position because it is the beginning of the body speaking to me. Has it been moved? Was there a struggle? Was the death quick or agonizing? In Darlene’s case it was clear that the attack was sudden, from behind, and death was almost instantaneous.
Blood Pattern Analysis:
Blood has specific properties—one of those is surface tension. Because of this feature of blood, it can be analyzed mathematically as to origin and angle of impact. There are numerous types of patterns: transfer, low, medium and high velocity patterns, pooling patterns and arterial spurt patterns. The patterns at a scene and on the body can give information of movement at the scene, sequencing of the wounds, and how many persons were at the scene. Because of the importance of blood patterns, scene security and processing must be treated meticulously.
This term refers to the rigidity of the muscles of the dead person. It is no accident that a common term for a dead person is “stiff”. Your muscles hold their tone and are able to contract and release through a complex chemical reaction of two molecules in the muscle cells: actin and myosin. Two chemicals, acetyl triphosphate and acetyl diphosphate allow this to happen. When a person dies the body is in a particular position. Left in that position for a period of time, the body will reach full rigor or stiffness. This happens because the two chemicals ATP and ADP are not going through their normal cycle. So rigor starts right away, it strengthens throughout the body and reaches full rigor in about six to eight hours. The rigor will leave the body in about twenty-four hours. Evaluating this helps provide a range for the time of death.
It is important to determine how far the muzzle of the gun was to the victim’s body at the time the weapon was discharged. The term sooting describes deposits of gunpowder residue on the skin of the victim. This burnt gunpowder can be washed or wiped off the body. Because it has little mass and would best be described as smoke residue, it can’t travel far from the barrel of the gun, so sooting is an indication of a close gunshot wound. Gunshot wounds are always described within a range. I define close range from near contact with the skin as approximately six to eight inches away from the target.
This is another term that relates to distance of the gun from the victim at the time of discharge. Stippling is partially burnt gunpowder residue. It has greater mass than the smoky, massless sooting residue and therefore can travel farther than soot. Once this unspent powder hits the victim’s skin it causes little red dots as it burns the epidermis, called “tattooing.” Booth sooting and tattooing can occur in a close rage shooting. If only stippling exists, then the gun was farther away. In my experience stippling occurs when the gun is eight inches to a little better than twelve inches away from target. All of these ranges depend upon the weapon and the ammunition used. Ranges can be reproduced with similar guns and ammunition to those in the incident by calibrating the distance from a whiteboard and then firing at multiple ranges.
A victimology is one of the keystones to deriving meaning from the evidence of an investigation. After the evidence is collected, documented and processed, the effort to give meaning to what all the evidence tells us is called “evidence reconstruction.” Evidence reconstruction begins with first studying the victim. This process is called building a victimology. The entire life is of importance, especially the last 48 hours before to death. In the first episode it readily became obvious that the victim knew the killer. There was passion involved in the assault. The victim was in the midst of trying to change her life as evidence of textbooks around the scene. A victimology must give meaning to why the victim was a victim.
Your DNA defines who you are uniquely. Most of your DNA is just like everybody else's but there are areas in the double helix that identify you more accurately than fingerprints. There is DNA in the nucleus of the cell, representing the profile of both the mother and father of the sample, and there is DNA from the engines of the cells, the mitochondria, representing only the maternal side of the sample. Each cell has many mitochondria, but only one nucleus. In most cases, mitochondrial DNA testing is done because a smaller sample is sufficient enough for identification.
The investigation of the mechanisms and forensic aspects of death--including the biological cause of death, the manner of death (homicide, suicide, accidental or natural), and the grieving process (social and psychological) for the families and loved ones left behind.
The word “coroner” is derived from the old English word “crowner.” Crowners worked for the king and their primary function was to travel to the king’s territories and investigate things such as fraud, other theft and yes, death. The king needed resolution of the deceased’s property since land distribution was determined by the cause and manner of death. The coroner held a position similar to the sheriff, only with greater emphasis on things “on or about the body.” By the twentieth century the coroner was generally someone with some medical background. In large populated areas such as New York, medical examiner systems developed.
Today most states have medical examiner systems or hybrid systems such as my office in Dauphin County, Pennsylvania. The systems depend on varying population areas, budget restraints and geographic conditions. The quality of the system is determined by the practitioners; I have met amazing individuals in both. I have a background in forensics and medical legal investigation and work very closely with a board certified forensic pathologist. All my deputies are nationally certified in medical legal death investigation and are constantly taking courses to keep their skill up to par with new advances in investigation, and investigative tools.
Whether in a medical examiner system or in a hybrid, the task is the same: recognize the evidence on or about the body, document that evidence, and process it through a chain of evidence. In the end we answer to no king. We cooperate with the police and law enforcement but our objective in not to charge or to arrest. Our mission is the solemn task of “speaking for the dead.” Ultimately, we are their advocates when they can no longer tell their story.
You would think that death is easy to define but it is not. Many states have different protocols for establishing the declaration of death. In general, death is when the body ceases to function in maintaining life. Death is death when it is irreversible. In most cases a person on life support must go through two separate electroencephalographs (EEG) over a period of time; say 24 to 48 hours. If the individual fails to have brainwaves sufficient to support respiration and heart rate the individual is termed “clinically dead”.
This is the scene where a crime or the cause of the death occurred. Whatever action caused the death happened at this scene.
This is an area where the body was transported to after the initial attack. This could be a dumping off point or an area secluded so the body could be hidden. Just because it is not the primary scene it doesn’t mean important facts can’t be found, tire tracks can lead to the perpetrator's car and at least tells you that the perpetrator drives. It may also indicate how familiar the perpetrator is with the area.
Chain of Evidence:
For the protection of the innocent and the prosecution of the guilty, there has to be an assurance that evidence is properly documented at the scene, collected in a manner that is scientific, processed and stored for examination. Each piece of evidence has to have a continuous documentation of who collected the evidence, where it was collected, the time and date it was collected, along with documentation of every person that touches the evidence and the purpose for handling the evidence. It is a chain of who handled the evidence and why.
A coroner or medical death investigator is often asked when the person died. Livor mortis can give the investigator a range of time as to when the person died. Unless you are looking at your watch and happen to see someone die, you will never be able to give an exact time, only an estimated range. One of the patterns on a dead body that can help establish the range of the time is a purplish discoloration. This is caused at the time of death when the heart stops circulating the blood and the blood goes to the dependent parts of the body. So imagine seeing a dead body lying, face down, on stair treads. The blood would flow towards the head. If the body is face down livor mortis would be present, much more so in the chest and face area. In most cases the color of discoloration is purple. It can be cherry red at times because of cold temperatures, carbon monoxide or arsenic poisoning.
Livor mortis tell us the position of the body due to the coloration of redness and blanching of white areas where the tissues are under pressure. If you push on your own hand right now, you will see, just for a second, the skin blanches and has a white or lighter spot where you applied pressure. The other these color patterns are movable at first but as the blood pools in these areas of the body the pressure starts to push the blood out of the small vessels and it begins to stain the area outside the cells. So within about six to eight hours the lividity or livor mortis will become “fixed”. This can tell the investigator that the death was not recent but most likely hours before he arrived on the scene. This information can be given to police and then compared to witness statements.
This is the temperature of the body when it is examined. It is compared to the normal human temperature of 98.6 Fahrenheit. When a person dies they stop producing energy in the cells and thus lose the ability to produce heat. There are many factors to determine the rate at which the deceased will lose heat from their body:
- What is the ambient temperature or room temperature where the body is found?
- What is the deceased body type: heavyset, thin or a more standard weight?
- What are they wearing?
- Where are they lying: on stone or cement, in water or on carpet?
- Is there constant air flow over the body?
All these factors and many more can influence how quickly heat can leave a dead body. As a very general rule, given room temperature, normal clothing, normal body temperature at death, in the first hour the deceased will lose approximately 2 degrees Fahrenheit and then approximately 1 to 1.5 degrees each hour after.
Again this is a rough approximation and never an exact science. Many times checking the cell phone records, the mail at the door or the statements of witnesses can give you a much or better time of death. It is still good to be able to calculate these ranges and see if they concur with other data.