Biology Presentation 2013
-
Upload
javierjones -
Category
Documents
-
view
226 -
download
0
Transcript of Biology Presentation 2013
-
8/12/2019 Biology Presentation 2013
1/57
IOLOGY
-
8/12/2019 Biology Presentation 2013
2/57
The application of science to the law/criminal investigations.It applies the knowledge and technology ofscience for the definition and enforcement ofsuch laws.Extremely popular these days especially ontelevision
- CSI
- Law & Order- Forensic Files etc
-
8/12/2019 Biology Presentation 2013
3/57
Several persons involved in the developmentof forensic science
Leone Lattes(1887-1954)Devised a relatively simple procedure fordetermining the blood group of a driedbloodstain, a technique that he immediately
applied to forensic science.
-
8/12/2019 Biology Presentation 2013
4/57
Edmond Locard(1877-1966) Locards xchange Principle
The exchange of materials
between two objects that occurswhenever two objects come intocontact with one another
Basically: Every contact leaves a
traceThis is the basis of forensic science
-
8/12/2019 Biology Presentation 2013
5/57
Can be a room or a large open lot Very important and must be managed properly The first officer on the scene is critical because
he secures the scene (cordon off) and calls thenecessary specialists ( forensic scientists,
pathologist, bomb squad etc) Log book must be kept at the scene to register
who goes in and out. Must be properly documented and recorded
(sketches, photos etc) and pictures of evidencetaken.
The chain of custodybegins here. Point ofcollection to when it gets to Court.
-
8/12/2019 Biology Presentation 2013
6/57
-
8/12/2019 Biology Presentation 2013
7/57
Physical evidencecan be found here i.e. anyobject that can establish a crime has beencommitted or can provide a link between acrime and its victim or between a crime andits perpetrator
SOC
Victim Accd/Susp
-
8/12/2019 Biology Presentation 2013
8/57
Types of Crime Scenes:
Sexual Assualt- hair, semen, blood,fibres
Murder- blood, fingerprint, firearmand ammunition, knife
Drug Raids narcotics, packages,chemicals
Arson- empty gasoline bottles,molotov cocktails (bottle bomb)
Fraud- documents, counterfeit Robbery- tools, paint chips, fibres, glass
-
8/12/2019 Biology Presentation 2013
9/57
Bloodstain Pattern Analysis:is the examination of the shapes,
locations, and distribution patterns ofbloodstains, in order to provide an
interpretation of the physical events
which gave rise to their origin.
Based on the prem ise that al l
b loodsta ins and bloodsta in pat terns
are character ist ic o f the forces that have
created them.
-
8/12/2019 Biology Presentation 2013
10/57
Bloodstain Patterns are classified as:
i) Passive Bloodstains patterns - results from
blood that has fallen due to gravity
-
8/12/2019 Biology Presentation 2013
11/57
A transfer bloodstain is created when a wet, bloody
surface comes in contact with a secondary surface. A recognizable image of all or a portion of the
original surface may be observed in the pattern, as
in the case of a bloody hand or footwear.
-
8/12/2019 Biology Presentation 2013
12/57
Transfer bloodstains can befurther subdivided into:
Contact bleedingSwipe or SmearWipe
Smudge
-
8/12/2019 Biology Presentation 2013
13/57
Cast-off StainsBlood released or thrown from a blood-bearingobject in motion:
-
8/12/2019 Biology Presentation 2013
14/57
Arterial Spurt / Gush
Bloodstain pattern s) resulting from bloodexiting the body under pressure from abreached artery:
-
8/12/2019 Biology Presentation 2013
15/57
Projected Bloodstain patterns
results as theblood source is impacted by some external forcegreater than gravity
It can be internally or externally produced
The size, shape, and number of resulting stains willdepend, primarily, on the amount of force utilized to
strike the blood source.
-
8/12/2019 Biology Presentation 2013
16/57
MEDIUM VELOCITY
Force of 5 to 25 feet/sec.Preponderant stain size 1 to 4mm in size
-
8/12/2019 Biology Presentation 2013
17/57
HIGH VELOCITY
Force of 100 feet/sec. and greater
Preponderant stain size 1mm in size and smallerMist like appearance
-
8/12/2019 Biology Presentation 2013
18/57
Altered Bloodstain patterns - results fromblood that was physically or physiologicallychanged
Altered Bloodstain patterns are :- Clots
- Diluted stains
- Stains altered due to insect activity
- Patterns created as a result of obstructionby an object
-
8/12/2019 Biology Presentation 2013
19/57
Protection be contamination conscious
Procurement collected evidence mustcoincide with documentation.
Package methods should not in any wayimpede or prevent testing.
Preserve ensure proper storage
-
8/12/2019 Biology Presentation 2013
20/57
Kastle Myer Test
Luminol
Precipitin
Marking of exhibits
-
8/12/2019 Biology Presentation 2013
21/57
Kastle meyer Test
The test are based on the peroxidase likeactivity of the haemoglobin in the blood.
The presence of Haemoglobin will acceleratethe oxidation of the phenolphthalin in thepresence of hydrogen peroxide.
Colourless reduced phenolphthalin is oxidisedto pink phenolphthalein.
-
8/12/2019 Biology Presentation 2013
22/57
Kastle- Meyer Kit
-
8/12/2019 Biology Presentation 2013
23/57
-
8/12/2019 Biology Presentation 2013
24/57
LUMINOL
A Chemical that reacts with the
Haemoglobin molecule in the blood toproduce different molecules andproduce light.
The light is only detected in darkenedareas
-
8/12/2019 Biology Presentation 2013
25/57
-
8/12/2019 Biology Presentation 2013
26/57
BLOOD
Determine the species of blood found : is it human
blood? PRECIPTIN TEST is an immuno-electrophoresis
reaction
-
8/12/2019 Biology Presentation 2013
27/57
Precipitin :An antigen antibody reaction
Antigen any substance that stimulates an
immune response ( human blood)
Antibody a specific protein produced by theimmune system in response to an antigen (anti-
human sera)
The antibodies react with antigens to form a
precipitate
-
8/12/2019 Biology Presentation 2013
28/57
Preci itin Electro horesis Tank
-
8/12/2019 Biology Presentation 2013
29/57
-
8/12/2019 Biology Presentation 2013
30/57
Confirming Human blood
Precipitate confirming that
blood source is human
-
8/12/2019 Biology Presentation 2013
31/57
CONFIRMATION TESTING
BLOODSeratec Hemdirect Assay
-
8/12/2019 Biology Presentation 2013
32/57
Bloodstain Item of clothing
-
8/12/2019 Biology Presentation 2013
33/57
Item with mixture of Blood and Semen
-
8/12/2019 Biology Presentation 2013
34/57
Weapon
-
8/12/2019 Biology Presentation 2013
35/57
Weapon
-
8/12/2019 Biology Presentation 2013
36/57
Acid Phosphatase Test
Microscopic Test for
Spermatozoa
-
8/12/2019 Biology Presentation 2013
37/57
Acid Phosphatase Test
Acid Phosphatase is an enzyme found in high
concentration in semen
Naphthol is liberated from the alpha napthyl
phosphate and reacts with diazonium compound
(Fast Blue) to form an insolouble coloured product
-
8/12/2019 Biology Presentation 2013
38/57
Semen stains turns purple
-
8/12/2019 Biology Presentation 2013
39/57
Vaginal
Anal
PenileOral/Buccal
-
8/12/2019 Biology Presentation 2013
40/57
VAGINAL SWAB AND SMEARS
-
8/12/2019 Biology Presentation 2013
41/57
Microscopic analysis is done to identify : Red blood Cells
White Blood Cells / Pus cells Spermatozoa
N. gonococci
red blood cell
Pus cells
-
8/12/2019 Biology Presentation 2013
42/57
Pus cells with gonorrhea causing
-
8/12/2019 Biology Presentation 2013
43/57
gonococci
Pus cells with gonorrhea- causing
bacteria
-
8/12/2019 Biology Presentation 2013
44/57
Trichomonas vaginalis
-
8/12/2019 Biology Presentation 2013
45/57
Azo-spermic males or males with extremelylow sperm count (oligo-spermic) due todiseases or defects or males that had a
vasectomy may not have spermatozoapresent in seminal fluid.
Confirmation Testing
-
8/12/2019 Biology Presentation 2013
46/57
Confirmation Testing
SEMEN
PSA p30 Test kit
a rapid test identifying prostatespecific antigen (PSA)
-
8/12/2019 Biology Presentation 2013
47/57
-
8/12/2019 Biology Presentation 2013
48/57
Sweat
Urine
Saliva Faecal matter (semisolid)
-
8/12/2019 Biology Presentation 2013
49/57
Alpha () amylase is the enzyme found in highconcentration in saliva
Alpha () amylase is also found in highconcentration in faecal matter and pancreatic
juices
-
8/12/2019 Biology Presentation 2013
50/57
Starch Iodine Test
Starch reacts with Iodine to produce a blue-blackcolour
The salivary alpha () amylase in an extract of
saliva stain will when added to starch solution
break down the starch to maltose and dextrins
Addition of iodine to this resulting solution will notproduce a blue- black colour. This is a positive
result.
-
8/12/2019 Biology Presentation 2013
51/57
Phadebas Test
A colourimetric commercial test
-
8/12/2019 Biology Presentation 2013
52/57
Phadebas Test
Phadebas reagent is comprised of starch being
linked or attached to a coloured dye to form starch-
dye complex.
In the presence of salivary amylase the starch is
hydrolyzed (broken down) and the dye is released
Blue dye form a blue stain in the area where saliva
is present
-
8/12/2019 Biology Presentation 2013
53/57
The basis of the test is to identify the presence of
creatinine
An extract is made of the stain by adding water
One drop of pictric acid and one drop of 5%
sodium hydroxide
The formation of a brown orange colour indicate
the presence of creatinine
-
8/12/2019 Biology Presentation 2013
54/57
-
8/12/2019 Biology Presentation 2013
55/57
Natural or synthetic Race of person Type of animal If root is presentthen DNA analysis
Natural or synthetic Class of syntheticfiber Colour comparison Texture comparison
-
8/12/2019 Biology Presentation 2013
56/57
NEGROID
CAUCASIAN
ASIAN
-
8/12/2019 Biology Presentation 2013
57/57