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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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| 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. |
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Powders collected may be analysed to reveal any illicit drugs.
Photo courtesy of www.free-stock-photos.com.
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| 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. |
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| 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. |
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(Above ) Pollen of rare flowers are useful clues. Photo courtesy
of www.imageafter.com. |
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| 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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*The differences between soil composition are very evident in the
samples above. Photos courtesy of www.imageafter.com.
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