From Evidence to Opinion: How Investigators Determine Cause and Manner of Death

By Jason Jones

October 14th, 2025

Death happens every day and is one of the few experiences guaranteed to every person at least once in their lifetime. Across the United States, the responsibility for investigating deaths falls squarely on the shoulders of medicolegal death investigators. These professionals are tasked with determining how someone died, why they died, and documenting the circumstances surrounding the death.

What Is Cause and Manner of Death?

The cause of death refers to the specific disease, injury, or event that directly leads to a person’s death. The manner of death, on the other hand, is the legal classification of how that cause came about. In the United States, there are five manners of death: natural, accidental, suicide, homicide, and undetermined.

Natural deaths make up the majority of cases and occur when internal processes of the body fail due to aging, disease, or other physiological breakdowns. From the moment we are born, our systems begin to age and decline. Genetics, lifestyle, and environmental exposures can accelerate that decline, but ultimately, some organ or system will fail, leading to a natural death.

Accidental deaths occur when an unintended event causes fatal injury. Examples include car crashes, fatal falls, or the accidental discharge of a firearm. However, it’s important to note that some seemingly accidental acts—such as playing Russian roulette—may not be classified as accidents because the individual knowingly engaged in behavior with a high probability of death. Generally, medical examiners follow the guidelines established by the National Association of Medical Examiners (N.A.M.E.).

Suicides are deaths that occur solely at the hands of the decedent through some process that they could reasonably expect to die from. As N.A.M.E. states in their Guide for Manner of Death Determinations, “Suicide results from an injury or poisoning as a result of an intentional, self-inflicted act committed to do self-harm or cause the death of one’s self.”

Homicides are deaths that occur at the hands of another. Murders are medically classified as homicides. While all murders are homicides, not all homicides are murder. Murder is a legal definition, not a medical classification. For example, someone breaks into a home in a violent manner and is shot dead by the homeowner who is acting to protect themselves from perceived fear. The would-be burglar’s manner of death would be homicide, but the homeowner was within their rights to defend themselves and would likely not be charged with the crime of murder.

Undetermined deaths are, as the name implies, those that either lack enough evidence to be compellingly classified into one of the previous categories or present multiple possibilities where no single classification can be justified over another. For example, police find a skeletonized body in the woods, the bones show no signs of trauma, and there is no way to determine the circumstances surrounding the death. Until and unless some other evidence comes forward, this death would be classified as Undetermined.

Each state in the U.S. operates under one of three death investigation systems: a coroner system, a medical examiner system, or a hybrid system. For example, Georgia uses a hybrid model in which each county must either elect a coroner (who then relies on the state crime lab for autopsies) or operate its own medical examiner’s office.

A Hypothetical Case Study

Consider a hypothetical case. The names and events in the following story are completely fictitious, and any similarities to actual events are unintentional and regrettable. This case reflects the kind of confusion families sometimes experience regarding cause and manner of death.

One summer afternoon, a 58-year-old man named Robert went fishing with his teenage son at a small lake near their home. While standing on the dock, Robert suddenly clutched his chest, stumbled, and fell into the water. His son immediately jumped in and, with help from a nearby boater, managed to pull him back onto the dock within a few minutes. Despite their efforts and the quick arrival of emergency responders, Robert could not be revived.

Several days later, the family received the death certificate. It listed the cause of death as drowning and the manner of death as accident. Robert’s sister, Linda, was shocked. She recalled that witnesses had clearly stated Robert grabbed his chest before falling and believed the cause should have been listed as a heart attack—a natural death. She worried that her nephew would feel guilt over the classification, thinking that if he had acted faster, he might have saved his father from drowning.

In cases like this, the distinction can be complex. The death investigator’s or medical examiner’s conclusion likely relied on autopsy findings showing that Robert’s heart disease alone did not cause his immediate death. Instead, while a cardiac event may have contributed, the actual physiological mechanism that ended his life was drowning—his lungs filled with water after losing consciousness and falling into the lake. Therefore, even though his heart problem played a role, the direct cause of death was drowning, and since the fall into the water was unintentional, the manner was classified as accidental.

As mentioned before, there is no standardized national system for death investigation. Each state establishes its own, and because of that, cases like the one above may be ruled differently in different jurisdictions. Organizations like N.A.M.E. seek to standardize outcomes as much as possible, but the variables for each case are extensive, and the differing systems throughout the U.S. can lead to varying opinions when it comes to cause and manner of death.

The Role of the Death Investigator

Situations like Robert’s highlight why death investigations require careful analysis of both medical findings and the circumstances surrounding the event. Death investigators often serve as the bridge between science and the grieving family, explaining how legal and medical standards define cause and manner of death.

It’s not uncommon for families to feel confused or even frustrated when the findings don’t align with their perceptions of what happened. The manner of death that appears on a death certificate is an opinion—it’s not a guess. The opinion must be supported by facts that would lead a trained medical examiner or coroner to reach that specific conclusion. In many jurisdictions, the legal standard to reach a determination is “reasonable medical or investigative probability,” meaning more likely than not, or a greater than 50% chance.

However, the classification system ensures consistency across jurisdictions, helps public health officials identify patterns of mortality, and supports the justice system in distinguishing between natural, accidental, and intentional deaths.

Some of the most difficult cases death investigators and police handle are suicide cases. Often, the families of the deceased are unwilling to come to terms with the facts and, in many cases, grasp at inconsequential information to present to investigators as proof the suicide was anything but a suicide. Unfortunately, there are many private-sector investigators or forensic consultants who will accept cases like these and agree with families solely to take payment. This is harmful in many ways. It undermines the credibility of legitimate investigators, creates false hope for grieving families, and distracts from the factual and scientific analysis that should remain at the heart of any death investigation.

There are certainly cases where investigators misinterpret evidence and reach improper conclusions or miss other items of evidence, though these cases are rare. When deaths of this nature occur, it’s important to remember that family members are grieving—and they have the benefit of believing the best of their loved one. The police, the coroner, or the medical examiner’s office must look at the facts and attempt to do so in an unbiased manner. The family member is under no obligation to shed their biases, nor should they be expected to have the same objectivity as trained professionals.

Another Hypothetical: Investigative Bias

In another hypothetical, John and Sarah are in the middle of a divorce. John moves out and rents an apartment. Sarah calls the police one Sunday morning because she was unable to get John on the phone and is now at his apartment. The doors are locked. Police arrive and force entry to find John deceased with a gunshot wound to the chest.

The police, the medical examiner’s investigator, and the medical examiner all examine the evidence, and the medical examiner feels confident the manner of death was suicide. John’s brother, however, believes Sarah killed him. The police conducted a thorough investigation and confirmed the doors were locked from the inside. The medical examiner conclusively determined that the gunshot wound was press-contact and consistent with John having held the gun. A bloodstain pattern analyst examined John’s hands and found spatter consistent with him having fired the weapon. These are all compelling indicators of suicide, but John’s brother remained unconvinced.

When asked how he was so certain John didn’t kill himself, the brother replied, “I spoke to him yesterday—he sounded fine and said he’d see me later.” In the brother’s mind, this was proof beyond reasonable doubt that John didn’t kill himself. In reality, this is extraneous and biased information that weighs poorly against the relevant physical evidence. This illustrates the role emotion and grief play in perception—how powerful cognitive bias can be when personal loss and disbelief override logic.

In some cases, however, the bias can come from investigators themselves. Imagine the same situation, but John had a documented history of suicidal behavior years earlier. Investigators, aware of that history, may unconsciously anchor on it and interpret new evidence through that lens. In this version, Sarah is found with blood on her hands and shirt—she claims she tried to help after hearing the gunshot. However, blood pattern analysis shows she was close enough to have been present at the moment the gun discharged. Despite this, the investigative team weighs John’s past mental health history more heavily than the current forensic findings and still concludes the manner of death as suicide. Later review reveals that their conclusion was driven less by evidence and more by expectation.

This scenario highlights how even experienced professionals can succumb to confirmation bias, giving greater weight to information that fits an existing narrative. It underscores the importance of objectivity, peer review, and structured analysis in every death investigation.

Final Thoughts

Death investigation is a field that blends compassion with science and law. For every case, investigators must evaluate the evidence, balance medical data with scene context, and reach conclusions that stand up to scrutiny in both courtrooms and families’ hearts. While the loss of life will always be deeply personal, understanding how and why a death is classified can bring clarity—and sometimes closure—to those left behind.

TriStar Forensic Consulting has unique experience in death investigations and is prepared to assist in examining your case to ensure no detail was ignored. While TriStar generally accepts cases in Georgia and Tennessee, we are capable of examining cases nationally.

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Reference

National Association of Medical Examiners. (2002). A Guide for Manner of Death Classification [PDF]. https://name.memberclicks.net/assets/docs/MANNEROFDEATH.pdf