The evidence you need to analyse
Chemical evidence
1) KM testing and Blood typing
The blood is one of the most important types of evidence that can be found on any crime scene is
always found when someone is injured can be any type of injury but is the second easiest and fasts
way to find the suspect just by comparing the blood type and the DNA in the blood. One of the most
used method the Forensic science use to find is the blood I human or animal or what kind of blood it
is or even if is blood or just a colour they use the presumptive blood test this blood test also helps
you to detect how closely can be associated with the victim or the suspect blood this test is carried
out by applying one drop of phenolphthalein and a drop of hydrogen peroxide solution on the
sample collected and wait until you see any changes and if no changes happens that’s mean that the
sample collected is not blood as you can see in the picture .
In the other hand if the sample collected is positive and the colour turn pink in this case we must tun
another test that identify the group type of the blood.
The type of group test.
Our blood is mainly made up from 3 important substance, red blood cells white blood cell and
plasma and there is 4 type of blood A, B, AB AND O each type are identified using an antibody and
antigens
We had to carry out this type of experiment to understand how we can identify the group type of
the blood and see the difference that happens when you apply antibodies to the blood as you can
see in the picture that in the first columns, we used antibody A on all the different type of blood, and
we saw the change only in blood type A and AB why? Because these two-blood type only react with
, an anti A antiserum, but blood type B have antibodies against type A blood or (anti A antiserum) so
that why it doesn’t change colour instead type O blood contain both anti A and anti B antibodies
Precipitate formed
Group A Group B Group AB Group O
Anti A antiserum From brown to No change Light brown No change
light brown
Anti B antiserum No change From brown to Light brown No change
light brown
We had to run this test before looking at the case so we can understand the different type of blood
and how to identify them using a very easy way Victim:
Sample Observation with anti Observation with anti BLOOD TYPE
A did clumping occur? B did clumping occur?
Mr smith No No O
Victim yes No A
Crime scene 1 No Yes B
Crime scene 2 No No O
The fact that Mr. Smith's blood matches the blood that was discovered at crime scene two indicates
that he was present during the crime scene. The results' accuracy would be improved by more
analysis, which would be necessary. By doing more testing, it would be accomplished. doing further
tests, such as the anti-Rhesus antibody test. These improve the accuracy and integrity of the
Chemical evidence
1) KM testing and Blood typing
The blood is one of the most important types of evidence that can be found on any crime scene is
always found when someone is injured can be any type of injury but is the second easiest and fasts
way to find the suspect just by comparing the blood type and the DNA in the blood. One of the most
used method the Forensic science use to find is the blood I human or animal or what kind of blood it
is or even if is blood or just a colour they use the presumptive blood test this blood test also helps
you to detect how closely can be associated with the victim or the suspect blood this test is carried
out by applying one drop of phenolphthalein and a drop of hydrogen peroxide solution on the
sample collected and wait until you see any changes and if no changes happens that’s mean that the
sample collected is not blood as you can see in the picture .
In the other hand if the sample collected is positive and the colour turn pink in this case we must tun
another test that identify the group type of the blood.
The type of group test.
Our blood is mainly made up from 3 important substance, red blood cells white blood cell and
plasma and there is 4 type of blood A, B, AB AND O each type are identified using an antibody and
antigens
We had to carry out this type of experiment to understand how we can identify the group type of
the blood and see the difference that happens when you apply antibodies to the blood as you can
see in the picture that in the first columns, we used antibody A on all the different type of blood, and
we saw the change only in blood type A and AB why? Because these two-blood type only react with
, an anti A antiserum, but blood type B have antibodies against type A blood or (anti A antiserum) so
that why it doesn’t change colour instead type O blood contain both anti A and anti B antibodies
Precipitate formed
Group A Group B Group AB Group O
Anti A antiserum From brown to No change Light brown No change
light brown
Anti B antiserum No change From brown to Light brown No change
light brown
We had to run this test before looking at the case so we can understand the different type of blood
and how to identify them using a very easy way Victim:
Sample Observation with anti Observation with anti BLOOD TYPE
A did clumping occur? B did clumping occur?
Mr smith No No O
Victim yes No A
Crime scene 1 No Yes B
Crime scene 2 No No O
The fact that Mr. Smith's blood matches the blood that was discovered at crime scene two indicates
that he was present during the crime scene. The results' accuracy would be improved by more
analysis, which would be necessary. By doing more testing, it would be accomplished. doing further
tests, such as the anti-Rhesus antibody test. These improve the accuracy and integrity of the
