Two of the most common questions I hear from crime writers are:

1. what would a body look like after a certain amount of time?

2. how long would a body have to be deceased before it looks a certain way?

These questions often lay the foundation for the murder at the heart of a crime story. From here authors can develop timelines for suspects, missing peoples, and witnesses. It is important to get it right.

While the question may seem simple to answer, it isn’t. In fact, an entire subfield of forensic anthropology is dedicated to the topic of what happens to a body after death and how to estimate how long someone has been dead. The field is called taphonomy.

The briefest overview of human decomposition

Decomposition refers to the breakdown of organic material. Human decomposition is an incredibly complex process dependent on an intricate interplay between diverse variables. Such variables can be environmental, cultural, living, inanimate and everything in between. The most important factor influencing the rate of decomposition is temperature.

Human decomposition can be broken into 5 stages: fresh, bloat, active decay, advanced decay, and skeletonization. The fresh stage and even into the bloat stage are generally handled by pathologists and include early changes such as algor, liver, and rigor mortis and bloating.

Estimating PMI

The latter stages of decomposition are when estimating postmortem interval (PMI) or time since death becomes more tricky. Researchers have developed methods to solve this problem employing insects, plant roots, bacterial colonies, and more. In 2005, Megyesi and her team1 came up with an ingenious method that, although not without flaws, provides a starting point for assessing PMI based on temperature and body condition.

Megyesi and her team knew that temperature was the most influential factor shaping the rate of decomposition but that it was difficult to account for both time and temperature in different environments when attempting to assess PMI. They developed an approach called Accumulated Degree Days (ADD) to account for this challenge. Essentially, the average temperature (in Celsius) for every day that a person has been deceased is added up to get the total ADD.

This approach is clever because now anthropologists could easily compare the condition of a body after 5 days at 10°C (ADD = 50) and a person missing for 2 days at 25°C (ADD = 50). This method also accounts for the fact that decomposition slows or stalls at freezing temperatures (0° C) because bacteria don’t function below freezing.

The team then developed a method to score the stage of decomposition across different regions of a body to produce a total body score (TBS) using the descriptions below. As you can see, the lowest possible scores is a 3 and the highest is 35.

A *magic* equation

The equation they developed correlated TBS and ADD and can be used to calculate one from the other: ADD= 10^(0.002*TBS*TBS + 1.81) ± 388:16

Here is how it works, using an illustration of a pig carcass as an example:

Decomposition here would be scored as follows: Trunk = 8; Head = 9; Limbs = 7 for a TBS of 24. Which is plugged into the equation as follows: ADD= 10^(0.002*24*24 + 1.81) ± 388:16. (You can enter the equation into google or ChatGPT for some help with the math.)

The result is 916.22 ± 388:16 or 528.06 –1304.38. So it would take between 528 and 1304 accumulated degree days to reach the stage of decomposition seen in the image. A forensic anthropologist would then gather local temperature data and add up the average of each day, working backward from the day of discovery. If the average temperature every day is 25°C then the individual would be deceased between 21 days and 52 days.

The equation also works backward. If an individual has been deceased for 10 days at 20°C, the ADD would be 200. Therefore, 200= 10^(0.002*TBS*TBS + 1.81).

Chat GPT can help you solve for TBS here, which is 15.66. Using the tables above a combination of features from each column can be selected to add up to 15. The trunk would be discolored with release of gases, the head would show bloating, and the limbs would be brown to black.

Using this approach authors can determine how long a body would have to be deceased to appear the way they need to it to or what a body would look like after being deceased for a given amount time.

A few notes:

• The Megyesi and team equation is only useful for remains that have been decomposing on land and were not buried. Buried remains tend to decompose slower, and remains in water are subject to several additional variables.

• Several teams23 have published updates to the study of Megyesi et al and have suggested more accurate or different approaches. However, this approach provides a level of accuracy necessary for fiction writing and is the easiest to use, so I recommend it to authors who need a place to start.

Incorporating truly accurate forensic anthropology into crime fiction can be a lot of work. When wading through the mountains of scientific research to figure out how fast crabs can consume a body in a freshwater lake or what size of bone fragments are left behind when a body is fed through a wood-chipper (there are real studies on these questions), authors can begin to question if all that work is worth it.

I can assure you the hard work pays off and not just because it satisfies nit-picky forensic anthropologists (like me). Incorporating accurate forensic anthropology into your next crime fiction story has three essential benefits: improving structure, enhancing audience engagement, and providing inspiration.

Structure

The structure of a story provides a skeleton (pun intended) for organizing events, crafting relationships between characters, and keeping the reader on track. Authors may be concerned that adding an accurate forensic investigation to a story can add too much complexity. However, forensic investigation contain their own structure that can be fit into an existing story arc and may actually provide structure to particularly complex stories.

Much like a traditional story arc, forensic investigations include all an inciting event, rising action, climax, and conclusion. An inciting event initiates an investigation, like a witness tip. The rising action leads up to the climax and can include a search and recovery. The climax is the turning point and can be the moment the forensic anthropologist makes a major discovery such as the identity of the victim or circumstances around their death. Falling action and conclusion is the wrap up and resolution of a case which can include communicating findings with law enforcement and working with them to put the last pieces together.

When a story begins to get unwieldy, returning to this structure can provide much needed foundation for rich and complex stories and characters.

Audience engagement

Using accurate forensic anthropology can also keep your audience stay immersed in your story and on the edge their seat by providing believability, logical consistency, and trust.

Nowadays everyone has some knowledge of science, forensic science, or true crime. False or conflicting information, therefore, will be recognized by readers to some extent and can jar them from the story and the world the author has created. When this happens readers lose enjoyment in the story, or in the worst case scenario, put the book down.

Using accurate forensic science also means that the all of the evidence, information, and finding presented in a case will make sense and be consistent. It is easier to look something up rather than trying to keep keep track of a plethora of made up facts and science. Readers will lose faith in a story and an author if the story has too many logic gaps or inconsistencies. By maintaining believability and logical consistency authors can gain the trust of the audience, building a connection with them and increasing their investment in the story.

Providing Inspiration

Crime writers are incredibly creative and imaginative individuals. Forensic anthropologists, however, are not far behind. The forensic anthropology literature is full of unexpected and unique research projects and case studies that provide a nearly endless pool of ideas for fictional murders and investigations. Studies have examined effects of coca cola on bone and tissue, whether skulls explode in fire or not, if bone fragments can be traced to a specific wood-chipper, and how to identify if a body has been attacked by a shark. When inspiration is lacking, a quick search through an academic journal is a great place to start.

Unlike what many TV shows portray, a forensic investigation relies on a diverse team of highly specialized experts from crime scene technicians, to autopsy technicians, to entomologists, to DNA analysts, forensic anthropologists, and more. Thus, incorporating accuracy into forensic investigations in fiction, can inspire you to incorporate more characters to fill your investigative needs with quirky and rich backgrounds based in reality.

TL;DR

Incorporating accurate forensic anthropology can take work but doing so pays of in spades by improving story structure, enhancing audience engagement, and providing inspiration.

Subscribe to this page for more tips and inspiration for writing about forensic anthropology in fiction.

TV and movies might have you believing that forensic anthropologists do it all: track down suspects, interview witnesses, and single handedly solve the most lurid and complex crimes.

In reality, forensic anthropologists are highly specialized experts that are just one part of a complex team of professionals with a shared goal: finding answers. While they certainly work on the occasional sensational cases, forensic anthropologists can contribute to all sorts of investigations involving human remains.

What is the official definition of forensic anthropology?

Forensic anthropology, according to the American Board of Forensic Anthropology, is the application of the science and methods of biological anthropology to questions of medico-legal concern. We can break down the two parts of this definition.

Biological anthropology is the study of human bodies. Although lots of scientific fields study human bodies, biological anthropologists emphasize that bodies are a product of biology as well as culture. Simply put: genes provide the blueprint for our bodies, but how those are expressed and how are bodies are shaped is a result of what we eat, where we live, what we do, what we believe etc.

Medico-legal concern refers to questions of identity of unknown human remains and circumstances around death. Circumstances around death can mean how someone died but can also include the activities leading up to death as well as what happened to a body after death.

What do forensic anthropologists actually do?

Forensic anthropologists rarely work full time as forensic anthropologists. Instead, they are employed as professors, curators, or in a myriad of other roles and are invited to consult by law enforcement on a case-by -case basis. They have to network with and educate law enforcement in their geographic area to ensure they are called in on relevant cases. They are called on to answer the following questions:

1. Is a material human bone?: Forensic anthropologists are experts in human skeletal anatomy, as well as have significant knowledge of non-human bones.

2. Where are the remains?: They have the skills to search for and recover human remains. These skills come from the field of forensic archaeology.

3. Who are the remains?: They are experts in applying methods to assess age, biological sex, ancestral original, and stature and being able to recognize unique features of the skeleton useful in identification.

4. What happened to the remains around death?: They are able to reconstruct events around death by examining patterns of trauma and investigating taphonomy (what happened to the body after death).

Generally speaking, forensic anthropologists focus on remains that are skeletonized or at least significantly decomposed. Because of their broad range of specialized skills forensic anthropologists may be called into assist on cases ranging from a single suspicious bone fragment h to a mass grave. As awareness of their skills increase , they are being called in to assist in other types of cases such as searches for bodies, burned bodies, child and elder abuse, and trauma cases in recently deceased individuals.

Why does any of this matter for your crime fiction?

Employing an accurate definition of forensic anthropology in your writing allows you to craft rich characters, a compelling investigation, and a complex crime. Here are just some examples:

1. You have the opportunity to introduce a character with competing priorities and struggles, creating depth.

2. Instead of one person doing it all, you have the opportunity to introduce several colorful experts that work together to solve the crime.

3. You have the chance to create complex crimes for your forensic anthropologist to solve such as burned, mixed up, or fragmented bones that may seem unsolvable at first glance.

What topics do you want to learn more about in future posts?