Time of the crime
By Roger Byard
Every ‘whodunnit’ reader and amateur sleuth knows the vital importance of determining the time of death.
Yet, explains leading forensic pathologist Roger Byard – who worked on the infamous Snowtown barrels murders – in the ‘real world’ things are not always quite so simple.
Several years ago, I wrote an editorial for a forensic journal entitled ‘Timing - the Achilles heel of forensic pathology’ which I started with a quote from Einstein that said that ‘time is an illusion’.
He may well have been correct, however for lawyers, illusions are not generally admissible in court (unless of course it involves their perceived excellence in the field), and so the expectation of a very rigid estimation of time can become one of the most crucial aspects of a case.
The prosecution tends to want the time of an event to be reduced to minutes, whereas the defence would prefer it to be years; the obvious reason behind this polarisation is that the shortest time limits the number of individuals who may have been involved, and the longest time may implicate pretty much anyone.
It is very common on forensic programs on television for the somewhat quirky forensic pathologist to turn up to a death scene and prognosticate after a minimal examination that the time of death was clearly at two minutes past midnight. If only life were so simple.
My response to that is that it could well have been two minutes past midnight – but maybe plus or minus a week! The reason for my somewhat tongue-in-cheek modification of the time of death is that biological processes are not discrete boxes but are a continuum with every person responding differently.
One of my earliest complex cases was the now infamous Snowtown ‘bodies in the barrels’ serial killings. I will never forget the Friday morning when we were trying to work out exactly how to approach six sealed barrels which, as it turned out, contained eight whole and partly dismembered bodies.
This means that although the stages of change after death such as rigor mortis, falling temperature, decomposition and skeletonisation are standard, the time taken is extremely variable. It is affected by a person’s metabolism, health status, weight, the ambient temperature, degree of exposure and clothing.
Simple examples involving the acceleration of decomposition occur with obesity (larger bodies tend to hold heat for longer periods of time) and with high blood sugar levels in diabetes mellitus (high sugars enhance the growth of bacteria).
The time for the stomach to become empty after a meal, so-called gastric emptying time, used to be heavily relied upon in courts to establish a plausible period between eating and death. Although several high-profile cases relied upon this evidence for convictions, it is now recognised that this too is completely unreliable and that it is affected by a large number of variables ranging from the consistency of the food to the mental status of the victim. The most appropriate statement to be made if food is found in the stomach at autopsy is that death occurred some time after eating.
One of my earliest complex cases was the now infamous Snowtown ‘bodies in the barrels’ serial killings. I will never forget the Friday morning when we were trying to work out exactly how to approach six sealed barrels which, as it turned out, contained eight whole and partly dismembered bodies.
One of the surprising findings subsequently was the inability to obtain DNA profiles from the victims. Given that paleogenetic and ancient DNA laboratories can get material from dinosaurs after millennia this did not seem to make much sense. However, time can be kind or not to forensic material, and the fluid, oxygen-depleted environment of the barrels had simply broken down all of the material.
Although urban myth has it that the bodies were dissolved in acid, this was not the case as the acid that had been added to the barrels had been neutralised by the fluid seeping from the corpses.
An additional problem was also in determining the times of deaths as decomposition and partial preservation made this impossible. Sometimes the most honest statement is that the person has clearly died sometime between when they were reliably last seen and when their body was found. Most lawyers will accept this.
An example of preservation over years was a case of two rubber boots containing the remains of feet that were dredged up by a fishing boat in the Great Australian Bight. In this instance, despite the watery nature of the environment, DNA was successfully extracted and matched to a fisherman who had been swept overboard more than a decade earlier.
Examples of the effects of time being slowed are numerous and may sometimes confuse contemporary investigators. Tollund Man was a body retrieved from a peat bog in Jutland in northern Denmark in 1950. He was so well preserved that the incised wound to the throat and the noose around his neck were thought to indicate a recent homicide.
After careful evaluation it was instead determined that he had been the victim of a ritual sacrifice in the fifth century BC - so much for an accurate time of death at that scene!
Sometimes the most honest statement is that the person has clearly died sometime between when they were reliably last seen and when their body was found
The mummified remains of ‘Ötzi’, a late Neolithic hunter who lived between 3350 and 3105 BC, which were found in the Tyrolean Alps, were in such good condition that his tattoos were still visible.
Sometimes changes will occur after death that will also preserve bodies and confuse time of death evaluations. Adipocere, the so-called ‘fat of graveyards’ or ‘corpse wax’, is material derived from the breakdown of fats which replaces normal tissues and preserves the outlines of bodies.
Although it usually takes months or years to develop, adipocere may be found within days of death. Apparently during the exhumation of a large number of graves in Paris in the nineteenth century ‘many tons’ of adipocere were found. Rather than discarding this malodorous material it was allegedly sold to local soap and candle makers.
Thus, the above examples show us that time can be a somewhat nebulous entity in forensic practice, one that can easily confuse and/or mislead.
Perhaps it is true after all that even in science time remains an illusion?
Emeritus Professor Roger W. Byard AO PSM DSc held the Marks Chair of Pathology at the University from 2006-2023 and is currently Senior Specialist Forensic Pathologist at Forensic Science SA. He was awarded the title of Emeritus Professor by the University of Adelaide Council in 2023 for his distinguished and sustained service to the University.
Main image of Roger, with his dog Minnie, by Isaac Freeman, photographic editor of Lumen. Image of Roger in the mortuary supplied by author.