Unit 9 Time of Death:
Investigative techniques to record, sample, and analyse taphonomy evidence:
In regard to taphonomy evidence, which is the state of decomposition that the body is
in, in order to record the evidence SOCOs would firstly need to photograph the body.
This is important as it ensures that it can be looked at later without the body having
changed due to time. As well as this, any moving of the body or tampering during
postmortem examination should be okay as they will have the image to show what it
looked like at the time.
When sampling the evidence initially the ambient temperature is taken from the crime
scene, as well as the core temperature from the victim, which is best taken either
rectally or from the liver. This is so as the ADD can be later calculated. This should
then be noted in the crime scene notes so there is a record of these results to analyse
later. The weather in the area at the time should also be recorded as this can affect
the stages of decomposition occurring, and if this isn’t noted then this can distort the
estimation of the time since death.
In addition to the sampling of the evidence, observations should also be made by
specialists to get an estimation of the stage of decomposition the body is in. This is
important as it can help to give us a time of death. To do this, algor mortis, rigor
mortis, and livor mortis should be taken into consideration, as well as other main
characteristics portrayed during each stage of decomposition. For example, bloating,
or fluids, or the loosening of flesh etc. However, other factors in the environment
should be taken into consideration when analysing these characteristics. These
observations should also be written down in the crime scene notes to be looked into
later. From these observations the specialist could score the separate parts of the
body (head, torso and limbs) in order to work out the total body score.
Once these observations have been carried out the victim can then be transported for
further postmortem examinations to take place. For example, in our crime scene the
bone marrow in the femur was analysed for the presence of diatoms.
Evaluation of this technique to estimate time of death:
One strength is that the use of photography is used when observing the body, which
means that we have an accurate image of what the body looked like at the time. This
means that the body continuing to decompose over time will not hinder the
investigation.
In terms of taking the temperature of the body as well as the ambient temperature a
strength is that this is a more objective means of estimating the time of death in
comparison to observations of the body as there is a specific number to be identified.
The way at which the temperature is also taken also helps in making this more
accurate, as the liver is a large internal organ that is quite easy to access for this, as
well as it not being directly exposed to the environment, meaning the outside factors
do not affect this as much. This also means that it cools down at a slower, steady rate.
However, it is most commonly taken rectally as this is easier to access, despite the
fact that this produces slightly less accurate results.
, A limitation of using just this one technique, is that there will always be outside
factors that will affect these results, so they will not remain accurate under certain
circumstances. This means that the techniques should all be used together and this
way a more accurate estimation of PMI can be established.
A limitation of observations is that this is subjective, as it is based on the specialists’
interpretations of the body.
Investigative techniques to record, sample, and analyse entomological evidence:
Before collecting any of the entomological evidence (insects) from the crime scene
SOCOs need to ensure that photographs of all the evidence have been taken before
anything is tampered with. From these photographs we can then see how many of
each species was present, which can help in estimating how long the body has been
deceased for.
Blow flies are the first insects to appear at the body, and though they commonly leave
by the time personnel arrive in the case that they haven’t they can be collected using
a hand-held insect net, and then transferred into a plastic box. This box should have
small air holes in them to ensure the blow flies don’t die. These should be looked for
around the body or near it as they will be getting ready or in the process of laying
eggs.
If there are eggs at the scene then these should be collected using very fine forceps
or sometimes a brush as they are very small. The eggs should be kept in a cool
environment when being transported so as to slow the development of them, however
it is good to keep some alive so as they can develop into flies so the species can be
identified more easily. The eggs are mostly laid by blow flies in wounds on the body or
under the body so SOCOs should look around these areas.
The three larval stages when the eggs have developed into maggots should all be
collected using forceps or a teaspoon. The first stage is still very small so fine forceps
should be used for this, though the next two stages are big enough for medium sized
forceps to be used. The maggots will leave the site where the eggs were laid so
SOCOs should look all around the body and near it for them. The maggots should be
killed in order to prevent them from developing further for later analysis. However, it
is good to keep some alive for them to develop into flies so the species can be
identified more easily. To preserve them they should be transferred into hot water,
around 80oc. They can then be placed into a preservative, typically 70-80% of ethanol
around 30 seconds after submersion in the water.
If there are flesh flies present at the body then these should also be collected in the
same way as blow flies were, using a hand-held insect net. These should then also be
places into a plastic container with air holes so as they do not die.
If the body has been there for a longer period of time, then beetles will begin to arrive.
Beetles can be picked up using forceps or hands, so long as gloves are being worn.
These can then be placed into a vial containing ethanol, so they do not continue to
develop further, much like the larvae.
With all of these insects, when they have been packaged, they should be labelled to
ensure they do not get mixed up. This label should include the location of the scene,
the date and time they were collected, the case number so it can be referred back to,
Investigative techniques to record, sample, and analyse taphonomy evidence:
In regard to taphonomy evidence, which is the state of decomposition that the body is
in, in order to record the evidence SOCOs would firstly need to photograph the body.
This is important as it ensures that it can be looked at later without the body having
changed due to time. As well as this, any moving of the body or tampering during
postmortem examination should be okay as they will have the image to show what it
looked like at the time.
When sampling the evidence initially the ambient temperature is taken from the crime
scene, as well as the core temperature from the victim, which is best taken either
rectally or from the liver. This is so as the ADD can be later calculated. This should
then be noted in the crime scene notes so there is a record of these results to analyse
later. The weather in the area at the time should also be recorded as this can affect
the stages of decomposition occurring, and if this isn’t noted then this can distort the
estimation of the time since death.
In addition to the sampling of the evidence, observations should also be made by
specialists to get an estimation of the stage of decomposition the body is in. This is
important as it can help to give us a time of death. To do this, algor mortis, rigor
mortis, and livor mortis should be taken into consideration, as well as other main
characteristics portrayed during each stage of decomposition. For example, bloating,
or fluids, or the loosening of flesh etc. However, other factors in the environment
should be taken into consideration when analysing these characteristics. These
observations should also be written down in the crime scene notes to be looked into
later. From these observations the specialist could score the separate parts of the
body (head, torso and limbs) in order to work out the total body score.
Once these observations have been carried out the victim can then be transported for
further postmortem examinations to take place. For example, in our crime scene the
bone marrow in the femur was analysed for the presence of diatoms.
Evaluation of this technique to estimate time of death:
One strength is that the use of photography is used when observing the body, which
means that we have an accurate image of what the body looked like at the time. This
means that the body continuing to decompose over time will not hinder the
investigation.
In terms of taking the temperature of the body as well as the ambient temperature a
strength is that this is a more objective means of estimating the time of death in
comparison to observations of the body as there is a specific number to be identified.
The way at which the temperature is also taken also helps in making this more
accurate, as the liver is a large internal organ that is quite easy to access for this, as
well as it not being directly exposed to the environment, meaning the outside factors
do not affect this as much. This also means that it cools down at a slower, steady rate.
However, it is most commonly taken rectally as this is easier to access, despite the
fact that this produces slightly less accurate results.
, A limitation of using just this one technique, is that there will always be outside
factors that will affect these results, so they will not remain accurate under certain
circumstances. This means that the techniques should all be used together and this
way a more accurate estimation of PMI can be established.
A limitation of observations is that this is subjective, as it is based on the specialists’
interpretations of the body.
Investigative techniques to record, sample, and analyse entomological evidence:
Before collecting any of the entomological evidence (insects) from the crime scene
SOCOs need to ensure that photographs of all the evidence have been taken before
anything is tampered with. From these photographs we can then see how many of
each species was present, which can help in estimating how long the body has been
deceased for.
Blow flies are the first insects to appear at the body, and though they commonly leave
by the time personnel arrive in the case that they haven’t they can be collected using
a hand-held insect net, and then transferred into a plastic box. This box should have
small air holes in them to ensure the blow flies don’t die. These should be looked for
around the body or near it as they will be getting ready or in the process of laying
eggs.
If there are eggs at the scene then these should be collected using very fine forceps
or sometimes a brush as they are very small. The eggs should be kept in a cool
environment when being transported so as to slow the development of them, however
it is good to keep some alive so as they can develop into flies so the species can be
identified more easily. The eggs are mostly laid by blow flies in wounds on the body or
under the body so SOCOs should look around these areas.
The three larval stages when the eggs have developed into maggots should all be
collected using forceps or a teaspoon. The first stage is still very small so fine forceps
should be used for this, though the next two stages are big enough for medium sized
forceps to be used. The maggots will leave the site where the eggs were laid so
SOCOs should look all around the body and near it for them. The maggots should be
killed in order to prevent them from developing further for later analysis. However, it
is good to keep some alive for them to develop into flies so the species can be
identified more easily. To preserve them they should be transferred into hot water,
around 80oc. They can then be placed into a preservative, typically 70-80% of ethanol
around 30 seconds after submersion in the water.
If there are flesh flies present at the body then these should also be collected in the
same way as blow flies were, using a hand-held insect net. These should then also be
places into a plastic container with air holes so as they do not die.
If the body has been there for a longer period of time, then beetles will begin to arrive.
Beetles can be picked up using forceps or hands, so long as gloves are being worn.
These can then be placed into a vial containing ethanol, so they do not continue to
develop further, much like the larvae.
With all of these insects, when they have been packaged, they should be labelled to
ensure they do not get mixed up. This label should include the location of the scene,
the date and time they were collected, the case number so it can be referred back to,
