Ninhydrin and NIK drug testing
Powdered fingerprint and handwriting analysis
KM testing for blood and hair analysis with DNA testing
Evaluation of the techniques used and comparing other possible methods
A CPS case file
Unit 23 Assignment 2 – Evidence Collection and Analysis
Ninhydrin and NIK drugs testing
Ninhydrin is a process that is used to find fingerprints on evidence that has been
collected from crime scenes. The specific piece of evidence that was tested in
relation to this case was a ransom note that was sent to the police from the
kidnappers. This method works by firstly spraying a small amount of 0.5%
ninhydrin in acetone onto the ransom note to lightly soak the page. The note was
then allowed to dry to ensure that the chemicals were completely absorbed into
the page. Then, the page was covered with a towel to prevent burning the note
as an iron was used to heat the note and bring out any fingerprints on the page
as the chemicals react with the amino acids from the sweat residue left behind.
This is done so that fingerprints that may not have been able to be found by just
looking at the evidence or with powder are uncovered and compared with those
of possible suspects.
NIK drugs testing is a process that is used to help identify what different
substances are that were found from crime scenes or found on suspects that
have been brought in for questioning. The evidence that was tested by using this
process was the bags of white powder that were found within the vehicle once
the collision had been analysed. The powder sample is placed into the small drug
testing bag and then sealed. The chemical that is inside a tube within the bag is
burst by applying pressure to allow the chemical and the substance being tested
to mix together. The powder should then undergo a colour change which
corresponds with a colour that indicates a different powder.
,Unit 23 Assignment 2 – Evidence Collection and Analysis
Powdered fingerprint and handwriting analysis
Powdered fingerprinting is a process that is used to help uncover fingerprints on
surfaces such as bottles, windows, bags, and much more. This process was used
within the car, and on the bottles, bagged powders, and drinks cans that were
recovered. The object or area that is being analysed is firstly dusted over with a
small amount of aluminium powder using a zephyr style squirrel brush. Once
prints have been found, tape is then used to help lift the prints from the surface
and the tape is then transferred onto a small square of clear plastic to help see
the prints clearer. All air bubbles are found out to ensure that all the detail in the
prints can be seen entirely.
Handwriting analysis is a process that can be used to link the handwriting of a
suspect to documents, notes, and letters. This is completed by providing a
paragraph that each suspect must copy out so that their handwriting style can
be seen to compare to, in this case, the letter written to the victim’s family.
Aspects such as word spacing, angles of letters, and the style of the handwriting
of each of the suspects that are being analysed are taken into consideration. This
is so that a link between the evidence and the analysis of each suspect can be
found.
, Unit 23 Assignment 2 – Evidence Collection and Analysis
KM testing for blood and hair analysis with DNA testing
KM testing for blood is a process that can be helped to identify if the red liquid
that is found at the crime scene can possibly be blood. This test is completed by
using cotton swab from the sample that was taken from the scene. It is then
placed into a solution of phenolphthalein and hydrogen peroxide solution. If there
is a positive indication of blood, then the solution shall turn pink due to the
solution reacting with the haemoglobin in the blood. If not, then it remains
colourless. If the results do end up being positive, it can only be referred to as a
possible blood presence as further testing must be done on the blood recovered
to provide more information.
Hair analysis with DNA testing is a process that can be used to identify who hair
samples taken from crime scenes may have come from. This helps to identify
any possible victims or suspects that could help to further build a case
surrounding the crime that has been committed. For this specific process, the
hair sample that was found inside the boot of the vehicle at the sight of the
collision was tested for DNA. The hair was recovered and observed underneath a
microscope to determine whether it was human hair or not. Once it was
confirmed that it was in fact human hair, it was sent for further DNA testing
which was performed within a lab. This step consists of adding chemicals to the
hair, removing the root cells for DNA, and viewing the sample underneath a
microscope once again to find links to possible victims.
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