Mollie McMillan
Environmental Forensics
Unit 9
Assignment A
In this assignment, I will be highlighting the stages of decomposition, including taphonomy
and entomology, and how this can relate to increasing/decreasing rates of decomposition,
how you can use this within forensics to establish things such as time of death and
definitions of such and also evaluating the practices of these methods.
Defining Death and the Laws around it
Death means that your ‘Tripod of Life’ (the normal function of the central nervous system,
circulatory and respiratory systems) stops. If one of these systems stops functioning, the rest
will follow and will lead to death. There are also legal ways to determine death, as set out by
the Uniform Determination of Death Act in 1980.
This act:
-defines death clinically
-does not include events such as suicide, the right to die or assisted suicide.
This act defines death as:
1. Irreversible cessation of circulatory and respiratory functions.
2. Irreversible cessation of all functions of the entire brain, including the brain stem.
Due to the fact a specific act like this exists, you can properly define death and when it
occurs, this then allows the forensic scientists to take over and work out things such as:
when did the death occur and how did they die? You can then also begin to use observations
like signs and external factors of death to fully determine this and when an autopsy and
analysis of a scene can be conducted. It provides a legal definition as to when death can
actually be determined based off of a set of rules, therefore death can be determined at an
official time and point, otherwise without this, people may have different definitions on when
somebody has died, so it allows a guideline to be set of when that can be properly
determined.
A disadvantage to this legislation is that it doesn’t define death for those who have
committed suicide or had an assisted death, therefore for these other methods of death,
you’d have to find other legislation to determine this, and it doesn’t state or cover all
situations in which death may occur, therefore reducing its effiency in the amount of ways
the legislation can be actioned.
The uses of forensic taphonomy and entymology
Forensic taphonomy is used to build up a profile of when a body has died, clues about how
the victim died, clues about a potential suspect. There are two types of taphonomy:
, ● Biotaphonomy - this is the study of biological factors relating to the decomposition of
a person. These can also be divided up into 3 factors being: individual (age/size of
the body), environmental factors (such as abiotic and biotic (non-living and living
organisms) and cultural factors.
● Geotaphonomy - the study of how the decomposing body effects the environment
around it, for example: footprints at the bottom of a grave, changes in the soils pH.
Taphonomy is useful because it can help locate where a victim has been buried/if they’ve
been moved for example, based on soil pH, how long the victim is dead, which can help link
a suspect to a particular area at a particular day/time. Without taphonomy, you’d have less
biological evidence as to when somebody died, so in court it could make it harder to link
anyone to the crime as there’s less exact proof as to when they died, however there can be
flaws to taphonomy, such as if weather conditions effect the rate of decay or things like the
burial grounds, such as if the body is exposed to air or not, which can make a time of death
estimate harder.
Entomology uses insects to help determine time of death, and how different insects can
affect the rate of decay and accelerate/decelerate decomposition of an organism.
Entomology is also useful because it can help detect things such as drug use, the length of
time a body has been in that area, and the location and time crimes occurred. It can also
help detect things like open wounds on a body, depending on where insects lay their eggs.
This can also help further determine cause of death, such as if it was abuse, any untreated
wounds or dirty/stained items of clothing, flies will be more attracted to. For drug use, insects
can be used by analysing sheddings of skin, and determine if the deceased was given or
taken drugs (can help in post-mortem for determining cause of death). Also for murder
cases, the specific types of insects around areas are analysed, so for example around a lake
the insects would be different then if they were to be in a forest, this can help determine if a
body has been moved or not, which is incredibly useful as you can see whether a suspect
has come back to a body/tried to hide or bury it so you can determine the actual location of
death and search that area for more evidence.
Algor Mortis
Algor mortis is the cooling of the body after death to the ambient (environment) temperature.
Algor mortis is due to the ‘cessation of the thermoregulation’ of the body (Rattenbury, 2017).
This means the body no longer is regulating body temperature, and has no cooling or
heating mechanisms, therefore it cools/heats up to ambient temperature. Algor mortis is one
of the most accurate ways of estimating TSD (time since death) within the early phases of
decomposition, this is because you can calculate the gradient with which the body has
cooled down and determine how close it is to its environment's temperature. This is because
a body can decrease 1.5 degrees Celsius every hour, therefore you can trace the time since
death back using the surrounding and internal body temperature. TSD is useful because it
can be used in court to eliminate suspects, and confirm or reject alibis made by defendants
or potential suspects based on where they were at the time the death occurred, and this
could lead to higher conviction rates, or potential innocent suspects being let off.
However, time since death can be found out in many ways, and this method can be hard to
use, as it requires detailed research and knowledge before it can be accurately used. This is
because different factors can affect ambient temperature, and therefore the temperature of
