How Does a Coroner Determine Cause and Manner of Death?

The Coroner Graham Hetrick

My job as a coroner is very different from that of police or prosecutors, whose job it is to obtain evidence concerning the perpetrator of a crime. My role is to tell the story of the dead and to do it in such a way that everything I learn can be admitted in court as evidence.

Essentially, I give the cause and manner of why a person has died. The cause of death is the actual mechanical reason why the human body has ceased to function. A person can die from loss of blood, but the important question for me is: What’s the reason for that blood loss? Is it Homicide, Accidental, Suicide or Natural? During my career, I have certified more than 13,000 deaths.

I approach the investigation of a person’s death like a conductor does. To me, it’s like bringing together the different parts of an orchestra. But instead of a string section, brass section, or percussion section, I conduct autopsies, forensic photography, toxicology, botany, odontology, and more. I tap my baton on the podium, each expert puts their knowledge to work, and I play the music — the music of the dead speaking to us.

To understand how the dead speak, a coroner needs to know their language. The scientific terms of death investigation are the backbone of any good medical/legal death investigator. Death investigation is a science, and every science has its terms. Because science is so exact, it requires precise definitions that are commonly agreed upon. One cannot just give an off-handed definition of rigor mortis, which is the stiffening of the muscles of the body for very specific biochemical reasons within the body after death. Rigor mortis has time lines and conditions that affect those reasons.

In the coming weeks, you will learn much about how I work and live. You will see me use both inductive and deductive reasoning, as well as the powers of observation, so that I can speak for the dead and tell their stories.

My terms are in my own language and defined by my 25 years of experience. It all starts with a hypothesis based on the data at the time. The hypothesis, or theory, must constantly be tested or challenged. Once you have tested all your theories and compared them to the data, the one left standing is most likely right. Learn some of the terms that every coroner knows:

1. Dead: 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.”

2. Primary Scene: This is the scene where a crime or the cause of the death occurred. Whatever action caused the death happened at this scene.

3. Secondary Scene: This is an area where the body was transported to after the initial attack. This could be a dumping-off point or a secluded area, so that the body could be hidden. Just because it is not the primary scene, that doesn’t mean important facts can’t be found there. Tire tracks can lead to the perpetrator’s car and at least tell you that the perpetrator drove. It may also indicate how familiar the perpetrator is with the area.

4. 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, and 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, and then there must be documentation of every person who touched the evidence and their purpose for handling the evidence.

5. Livor Mortis: A coroner or medical death investigator is often asked to determine when a person died. Livor mortis can give the investigator a range of time within which the person died. Unless you watch 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. At the time of death, the heart stops circulating the blood, and the blood goes to the dependent parts of the body. So, imagine seeing a dead body laying facedown on stair treads. The blood would flow toward the head. If the body is facedown, the livor mortis would be present much more in the chest and face area. In most cases, the color would be purple. It can be cherry-red in the case of cold temperatures, carbon monoxide, or arsenic poisoning.

The livor mortis tells us the position of the body because of this coloration and also the 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, that the skin blanches and there’s a white or lighter spot where you applied pressure. As the blood pools in dependent 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. In 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.

6. Rigor Mortis: 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 a “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, that body is in a particular position. Left there in that position for a period of time, the body will be in full rigor or stiffness. This is because those two chemicals ATP and ADP are not going through their normal cycle. Rigor starts right away; it strengthens throughout the body and becomes full rigor in about six to eight hours. The rigor will leave the body in about 24 hours. This also can help give a range for the time of death.

7. Algor Mortis: 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 a deceased person will lose heat from their body:

  • What is the ambient temperature or room temperature where the body is found?
  • What is the deceased’s 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, and 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 a rough approximation. Many times, checking the cell phone records, the mail at the door, or the statements of witnesses can give you a much better time of death.  It is still good to be able to calculate these ranges and see if they concur with other data.

To learn more about the terms and practices of a medical legal investigator, watch “The Coroner: I Speak for the Dead” Mondays at 10/9c on Investigation Discovery. Go to Graham Hetrick’s official website to learn other forensic terms. 

Photo courtesy of Investigation Discovery


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  • Dwayne Jordan

    Its sometimes a stretch to expect a coroner to determine the manner of death in all cases, I much prefer cause of death and let other fit the puzzle of manner of death.

  • Edvard

    The fact that you call ATP and ADP as acetyl triphosphate and acetyl diphosphate instead of Adenosine tri- and diphosphate, is such basic biochemistry, that I dont believe any person with medical education would have made that mistake, not even a medic… It is not potato, potato mr. Graham Hetrick.
    It is strange to me that in an supposedly advanced country, as the USA, a person with out any medical education, is eligible for Coroner, and that this non-medical elected official, can then be the one to determine if a suspicious death is du to accidental- homicidal- suicidal- or natural death. Also being an “expert” witness in criminal cases, holding the trust and confidence of a jury or court. This is total and utter lunacy.

  • Ann Stanton

    This is very interesting to me and I watch this as much as I can. When my sister died due to a significant medication error at a skilled nursing facility in Pittsburgh, her death certificate noted Hypoglycemic Coma as first and Anoxic Brain Injury as second and the death as Natural. When I questioned this at a later date, the doctor refused to amend the certificate even though he said he wasn’t aware of everything on the nursing home records that I sent. The State said I could contact the Allegheny Co Medical Examiner but he was not interested in reviewing the info and determining if an error was made on the death certificate. From what I had read, she could not come off life support (3 mos on it) due to her anoxic brain injury. It seemed to me that this would have been listed first and then the hypoglycemic coma, respiratory arrest, aspiration pneumonia and the injury would have been listed. They say a death cert is supposed to be as correct as possible so why won’t a Medical Examiner or doctor ensure this is done right?