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| Clues
From The Environment |
| The environment offers
many clues that, during the course of a day, we often overlook or
take for granted. The dust and dirt that accumulates on the bottom
of our shoes, minerals, fibres and seeds provide important clues about
the crime, as well as the suspect. These minute clues can often point
to the criminal's hobbies, occupation, habits and movements and are
often helpful in guiding an entire investigation. |
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Select a topic from below to learn more:
--> Collection
--> Basic comparison
--> Seeds and
pollen
--> Soil and dust
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| Copyright
2004-2005 Thinkquest Team 00206 |
| Collection |
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| Like the collection of
trace evidence, dirt and dust from a crime scene are collected using
tape or a forensic vacuum to lift the sample from its surroundings.
Once taken to a forensic laboratory, a careful analysis of the dust
and dirt samples can be conducted under controlled conditions. Large
particles in the sample are extracted, making the overall sample analysis
clearer. A complete soil analysis is rare because of time consumption,
but may be necessary depending on the case involved. |
| Copyright
2004-2005 Thinkquest Team 00206 |
| Basic
Comparison |
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| Less time consuming analyses are likelier
to be done when the simply matching of mud samples is required. A
direct comparison of the two samples is conducted, with investigators
looking for aspects such as colour similarities, pH
levels and the variety and size of the particles found in the
sample. For example, mineral particles will have traces of the rock
from which they were derived, such as quartz and limestone, while
grains of sand have distinctly different shapes if say, one comes
from the ocean and the other from a desert. |
| Copyright
2004-2005 Thinkquest Team 00206 |
| Seeds
And Pollen |
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Biological matter in a sample of soil such as leaves, compost,
pollen, seeds and spores from fungi are analysed also, for it too,
can pinpoint the sample's area of origin. Seeds from plants which
are only found in a certain areas provide a guide to tracking down
the place where the dirt originated and the pollen of plants are
also used in the same way, for example, in narrowing down a search
for a buried body by using a sample of soil found on a suspect's
clothing or car.
Seeds and pollen also provide accurate chronological details because
most plants only shed pollen or seeds at certain times of the year.
This information can not only prove that a suspect was in a certain
area at the time, but also what season and time of the year it may
have been. Most labs contain computer recorded databases of biological
matter, which when attached to a scanning
electronic microscope, are able to find identify certain
particles in a sample with those already on the database.
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| Soil
And Dust |
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Soils samples are analysed by biologists and mineralogists, who
provide investigators with details of the areas where particular
plants, seed and pollen may be found. The analysis of soil is used
mainly for the purpose of finding a certain place, usually a scene
of crime.
Dust, is equally as helpful as soil samples, as dust is different
in every house and is unique to every room of a house. Samples of
dust located in the bathroom often contain cosmetics, and powder
while samples found in the kitchen contain flour and spices. Animal
hair, skin cells, dust mites and fibres form clothing and carpets
also contain evidence unique to a certain house.
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