FORENSIC CHEMISTRY AND

TOXICOLOGY

BY: RHANETH H. OLVIS, RCRIM, MSCRIM, CCS, CSP, ASMS-1, FCTS

What is forensic?

 The word Forensic came from the Latin word

“forensis” meaning forum. Forum is the place
where debates took place and as such served
as the courtroom.
 The Scope of Forensic Chemistry

 The scope of forensic chemistry embraces a large and

diversified field. It includes not only the chemical side of
criminal investigations with which it is generally associated
with the public mind but also the analysis of any material, the
quality of which may give rise in legal proceedings.
According to Urbano (2008), “forensic chemistry invaded
other branches of forensic sciences notably legal medicine,
ballistics, questioned documents, dactyloscopy, and
photography”.
What is Forensic Chemistry?

 is the application of chemistry to identify and analyze

substances found at crime scenes in order to help
solve crimes. It involves the analytical study of
ph ysica l a n d ch e m ica l pro pe rt ie s o f m a t e ria l s
that might be easily misidentified or confused, with the
goal of determining their true identity and origin
 Forensic Chemistry occupies an important and unique
role in the criminal justice system; a role that relates to
the Forensic Chemists ability to supply objective and
accurate information through the physical evidences
collected which will reflect of the crime committed at
the crime scene.
 The proper collection, transport, preservation
and examination of physical evidences as well
as the personnel performing this duty is of utmost
importance because these physical evidences
will connect the perpetrator of the crime to the
crime committed
The Practice of Forensic Chemistry

The work of a forensic chemist is divided into four stages, namely:

1. Collection or reception of the specimen.
What are the factors to be considered when collecting specimen?
 Sufficiency of samples.
 Standard for comparison.
 Maintenance of individuality.
 Labelling and sealing
2. The actual examination.
The steps include:
 Scrutinize it carefully.
 Measure or weigh the object.
 Laboratory examination that includes chemical, physical, and
confirmatory tests.
3. The communication of the results of the examination
It is conducted in the form of a written report that must include the
following:
 Enumeration of the facts of the specimen received for examination with
detailed description of its:
 Packaging;
 Sealing; and
 Labelling;
 The date of receipt and from whom it was received;
 The purpose of the examination; and
 The finding and conclusion.

4. Court appearance. Forensic chemists are usually called to present and

testify in court about the about the forensic examination conducted.
 Forensic Chemistry includes the
following:

 Collection, preservation, examination and study of blood, semen, and

other body fluids;
 Examination of dangerous drugs;
 Examination of body fluids to determine the presence of dangerous
drugs;
 Alcohol (Liquor) test;
 Examination of fake products for unfair trade competition;
 Arson investigation;
 Macro etching examination;
 Bullet trajectory;
 Ultraviolet examination;
 Tools and other tool marks;
 Gunshot residues
 Principles and examination of explosives;
 Hairs and textile fibers;
 Glass fragments and glass fractures;
 Moulage; and
 Metallurgy and petrography.
 The Six Golden Rules in the Practice of
Forensic Chemistry

1.Go Slowly
2.Be thorough
3.Take Notes
4.Consult Others
5.Use Imagination
6.Avoid Complicated Theory
 Guidelines in preservation and safekeeping
of evidence

 Proper chain of custody shall be observed.

 All examined pieces of evidence shall be personally turned over by the
examiner on case to the evidence custodian.
 The latter, in turn, shall execute its documentation by recording all
received as well as released evidence for court presentation.
 No examiner shall keep in their possession evidence once examined.
 Evidence shall be properly placed in suitable dry containers for proper
preservation and shall be placed inside the concrete evidence room.
Urbano (2008) cited reasons that may lead to the loss
of evidence value, these are:

 Improper packing of specimen.

 Failure to identify the specimen.
 Improper precautions used in transmitting the
specimen.
 Improper preservation.
 Lack of precaution to prevent tampering of the
specimen.
Scientific Evidence
VALUE OF EVIDENCE

1. Defining the elements of the crime.

2. Providing investigative leas for a case
3. Linking a crime scene or a victim to a suspect
4. Corroborating or refuting a suspect’s statements
5. Identifying a suspect
6. Inducing a confession from a suspect
7. Exonerating an innocent
8. Providing an expert testimony in court
 METHOD OF IDENTIFYING PHYSICAL
EVIDENCE

1. Qualitative examination
- Physical test
- Chemical test
- Confirmatory test

2. Quantitative examination
 Physical Test

Chemical test Turn to blue color

Confirmatory Test
COMMON PHYSICAL EVIDENCE SUBMITTED TO PNP

Types of Evidence Nature of Case

Seized Drugs Alleged violation of RA 9165
Volatile Substance Alleged violation of PD 1619
Explosives and ingredients Alleged Explosives
Firearm, suspects hands, clothing Alleged Shooting Incident
Body fluids, food sample Alleged Poisoning
Fake Products Unfair Trade Competition
Urine and body fluids Drug Testing
Blood Alcohol RA 10586
Metal, paper, ink, woods etc Trace and Chemical Analysis
Modern-day criminal investigations known as forensic science is mostly done
by government police forces. When a serious crime is investigated, the
investigation process typically consists of four steps:

1.Physical evidence is collected at the crime scene by police officers or crime

scene investigators.

2. The physical evidence is analyzed by forensic scientists (often chemists) in a

laboratory.

3. All the evidence (that means the analyzed physical evidence plus other
evidence eyewitness stories , police reports, crime scene sketches and
interrogation, etc./ ) is interpreted by detectives/criminal investigator.

4. Evidence is presented in court.

 What is evidence?

It is a means sanctioned by law of ascertaining in a

judicial proceeding the truth respecting a matter of
fact (Sec. 1, Rule 128, Rules of Court). Evidence
establishes proof.

Thereby, proof is the end result of evidence.

 What is Scientific Evidence?

The evidence becomes scientific evidence when a certain

scientific knowledge is necessary.
Thus, scientific evidence may mean as: “the means
sanctioned by law of ascertaining in a judicial proceeding the
truth respecting a matter of fact wherein scientific knowledge is
necessary” (Caṅete 2010).
Under Sec. 3, Rule 128 of the Rules of Court, evidence is
admissible when it is relevant to the issue and is not excluded by
the law of these rules.
 What is admissibility of evidence and
probative value of evidence?

Admissibility of evidence refers to the questions of

whether or not the circumstance (or evidence) is to be
considered at all.
On the other hand, the probative value of evidence
refers to the question of whether or not it proves an issue
(PNOC Shipping and Transport Corp. vs CA, 297 SCRA
402).
Background
The case involves a dispute between PNOC Shipping and Transport Corporation
(PNOC) and the Court of Appeals (CA) regarding the liability for damages related
to the loss of a vessel and its equipment. The private respondent, a shipping
company, claimed damages for the alleged loss of its vessel due to the negligence
of PNOC.
Facts
 The private respondent's vessel was lost, and they sought to recover damages
from PNOC.
 In support of their claim, the private respondent presented price quotations for
the replacement value of the lost vessel and equipment.
 The trial court ruled in favor of the private respondent, awarding damages
based on the presented evidence.
The main issues revolved around:
1. The admissibility and weight of the evidence presented by the private respondent.
2. Whether the damages were proven with sufficient certainty.
Ruling
The Supreme Court overturned the decision of the lower courts, emphasizing several
key points:
1. Admissibility of Evidence: The price quotations were deemed inadmissible
hearsay because they were not accompanied by the testimony of the individuals
who prepared them. The Court highlighted that hearsay evidence cannot be
the basis for a judgment.
2. Proof of Damages: The Court reiterated that damages must be proven with
reasonable certainty and based on competent evidence. The private respondent
failed to provide such evidence, as the general manager's testimony was
insufficient due to lack of personal knowledge regarding the valuations presented.
3. Credibility of Witnesses: The Court noted that the testimony of the
private respondent's general manager was self-serving and lacked
objectivity, further undermining the claim for damages.
Conclusion
The Supreme Court concluded that the private respondent did not
adequately prove the actual amount of damages suffered. The ruling
underscored the importance of presenting competent and admissible
evidence in support of claims for damages, reinforcing the principle that
damages must be substantiated by reliable proof. As a result, the Court
reversed the lower cour ts' decisions and dismissed the private
respondent's claims for damages.
 Two requisites must concur for evidence to
be admissible:

1. It is relevant to the issue; and

2.It is competent, that is, it is not excluded by the
law or the rules of evidence.
 Two requisites of relevancy

A. Rational or Logical Relevancy. The evidence must

have a connection to the issue and therefore it has the
tendency to established the fact which is offered to
prove. The evidence therefore must have probative
value.

B. Legal Relevancy. The issue presented must be the

issue of the case.
 What is an exclusionary rule?

It is a rule of evidence which excludes

evidence obtained in violation of a
person’s constitutional rights or secured
through illegal means or sources.
 What is Fruit of the Poisonous Tree
Doctrine?

Under the exclusionary rule known as the “fruit of the

poisonous tree,” once the primary source (the tree) is
shown to have been unlawfully obtained, any secondary
or derivative evidence (the fruit) derived from it is also
inadmission. Generally, evidence may be indirect or
circumstantial, direct, and hearsay.
What is Circumstantial evidence?

Indirect evidence, presumptive

evidence. It proves a fact in issue
indirectly whereby reasoning or
inference is being drawn by the fact
finder
Direct evidence is an evidence directly proving a
fact, like testimony of witnesses. It proves a fact in
issue directly without any reasoning or inference
drawn by the fact finder.
 Security camera footage
 The defendant fingerprint
 A witness testifying they saw it raining outside
 A signed confession by the defendant
 What is Hearsay evidence?

It is a testimony of a witness as to the facts not

proceeding from personal knowledge of said
witness and is generally inadmissible as
evidence. It is also called as secondhand
evidence.
 Forms of Scientific/Medical Evidence

1. Real/autoptic/object evidence – this form of evidence is

addressed directly to the senses of the court. It is not limited
to that which can be known by the sense of vision but
extend to what is perceived by the senses of hearing, taste,
smell or touch.

Exceptions: (a.) indecency and impropriety; and (b.)

repulsive objects and those offensive to sensibilities.
 Object as evidence

Object is anything which comes within the

cognizance or scrutiny of the senses of the court,
like tangible or visible things. The relevant object
maybe:
1.Exhibited to the court
2.Examined by the court, or
3.Viewed by the court.
 2. Testimonial evidence

A physician may be placed at the witness stand to

answer questions propounded to him by counsels
of parties or by the presiding officer of the court. His
testimony must be given orally in open court and
under oath or affirmation.
3. Experimental evidence

A medical witness may be required to

perform certain experiments to pr ove a
certain matter of fact.
4. Documentary evidence

A written evidence presented by a physician

in court which is relevant to the subject
matter in dispute and not excluded by the
rules of court.
Test on Biological Evidence –
BLOOD AS EVIDENCE
 Why study blood?

 It is an important part of criminal investigation especially in many

cases of violent death. Blood evidence is of value in such crimes
as murder, rape, assault, robbery, burglary, hit-and-run accidents,
and game law violations. Blood evidence may aid an
investigation by locating the crime scene, by identifying the
weapon used, by proving or disproving a suspect's alibi, and by
eliminating suspects.
 DNA profiling can be performed on any biological substance. It
can also be used for the identification of bodies when samples
from parents and/or children of the missing person are available
(Evidence Collection Handbook, 2019).
 Importance of Studying Blood

Ø Circumstantial or corroborative evidence against or in favor the

perpetrator.
Ø Evidence in case of disputed parentage.
Ø Evidence in the determination of the cause of death, length of
time, the victim survived the attack.
Ø Evidence in the determination of direction of the escape of the
victim or assailant.
Ø Evidence in the determination of the origin of the flow of blood.
 Blood as Evidence: Its uses

Blood as evidence may appear in different forms:

 Blood samples – Can be analyzed to determine blood type and
DNA, which can be matched to possible suspects.

 Blood droplets – Can be analyzed to give clues to the location of a

crime, movement of a victim, and type of weapon.

 Blood spatter – Can be analyzed to determine patterns that give

investigators clues as to how a crime might have happened.
 Blood Facts

 It has been called as the circulating tissue of the body.

 It is referred to as highly complex mixture of cells, enzymes, proteins and
inorganic substances.
 It is faintly alkaline which has a normal pH of 7.35 to 7.45.
 The average adult has about FIVE LITERS OF BLOOD inside of their body,
which makes up 78% of their body weight.
 There are about one billion red blood cells in two to three drops of blood. For
every 600 red blood cells, there are about 40 platelets and one white cell.
What makes up our blood?
1. The 45 % are formed elements consisting
chiefly of cells

RED BLOOD CELLS – Erythrocytes

 The most abundant cells in our blood;
 They are produced in the bone marrow and
contain a protein called hemoglobin that carries
oxygen to our cells; and
 It is biconcave or donut shape.
WHITE BLOOD CELLS – Leukocytes
They are part of the immune system and
destroy infectious agents called pathogens;
Larger than red blood cells; and
Irregular shapes.
PLATELETS – Thrombocytes
 Irregular shaped cell fragments;
 The clotting factors that are carried in the plasma;
and
 They clot together in a process called coagulation to
seal a wound and prevent a loss of blood.
2. And the 55 % is PLASMA.

 This is the yellowish liquid portion of blood.

Mostly water 90% and 10 % solid that consists
albumen; several globulins and fibrinogens.
 Itcontains electrolytes, nutrients and vitamins,
minerals, hormones, clotting factors, and proteins
such as antibodies to fight infection
What are the chronological tests for
blood?

1. Preliminary test – this determines whether the stains

contain blood or another substance.

2. Confirmatory test – this possibly identifies blood.

Determines whether bloodstain really contains blood .
3. Precipitin test – this determines
whether the blood stain is of human
origin or not.
4. Blood grouping test – this determines
blood group.
 PRELIMINARY TEST FOR BLOOD

A. Benzidine test
An extremely sensitive test that can be applied to minute
stain. For many years the most commonly used preliminary
test for blood.
Positive result – intense blue color
 Phenolphthalein test
This is an alternative test to benzidine test. It can detect blood in a
dilution of 1:80,000,000 parts. A positive result with this test is highly
indicative blood. The negative result is therefore valuable and is
conclusive as to the absence of blood.
Positive result – rose color develops/ deep pink/ permanganate color.
The Guaiacum Test
 A fairly delicate test showing the presence of fresh
blood in a solution of 1:50,000 dilution. It may not react
to very old stain.

 Positive result – beautiful blue color

The Leucomalachite Green Test
 This test is an alternative method for detecting bloodstains. It
can detect blood in a dilution of approximately 1:100,000
parts, making it useful for identifying blood in less
concentrated samples, though not as sensitive as the
benzidine test.
 Positive result – malachite green or bluish-green.
The Luminol Test
 This is an important presumptive identification for blood. The creation
of luminal with blood results in the production light rather than color.
By spraying luminal reagent onto a suspected item, large areas can
quickly be screened for the presence of bloodstains.

 Positive result – luminescence or emission of light.

THE CONFIRMATORY TEST FOR BLOOD

 Theactual proof that a stain is blood consists of

establishing the presence of the characteristic
of blood pigment hemoglobin or one of its
derivatives. Hemoglobin is the red coloring
matter of the red blood cells of the blood.
THE THREE CONFIRMATORY
FOR BLOOD
 THE MICROSCOPIC TEST FOR BLOOD

 Microscopic test is useful for the demonstration and

mensuration of blood corpuscles for making the
distinction between mammalian, avian, piscine, and
reptilian blood for the investigation of menstrual,
lochial and nasal charges. In short it differentiates
mammalian, avian, piscine and reptilian blood.
THE MICROCHEMICAL TEST AND
MICROCRYSTALLINE TEST FOR BLOOD

 Theidentification of blood can be made more

specific if microchemical or microcrystalline test is
applied or performed. Takayama test and
Teicmann test are the most popular ones.
 THE TEICMAN TEST

 It is a microcrystalline test used to identify blood by detecting the

presence of heme, a component of hemoglobin. This test forms haemin
crystals from heme when treated with specific reagents.
 It is used to confirm the presence of blood in a sample and to validate
the presence of blood on surfaces, clothing, or other materials. It detects
blood effectively but depends on the sample's quality and condition.

 Positive result – dark brown rhombic crystal of haemin or haematin

chloride arranged singly or in cluster.
THE ACETONE-HAEMIN TEST

 A test that uses acetone to precipitate heme from hemoglobin,

followed by crystal formation to confirm the presence of
blood. Used to detect blood in cases where the sample
may be diluted or degraded. It is useful in forensic
investigations to confirm blood presence in challenging
conditions.

 Positive result: small dark, diachronic acicular crystals of

acetone haemin.
 HAEMOCHROMOGEN CRYSTAL TEST OR
TAKAYAMA TEST

 It is a delicate test for the presence of hemoglobin. It Identifies blood by

detecting haemochromogen, a derivative of heme. This test forms
haemochromogen crystals from the heme component of hemoglobin.
Used in forensic science to confirm blood presence in various sample
conditions, including those that are diluted or degraded.
 Positive result: Large rhombic crystals of a salmon pink color arranged in
cluster, sheaves and other forms that appear within 1-6 minutes when
viewed under the low power objective. To hasten result heat may be
applied.
The Genetics of Blood
 Your blood type is established before you are BORN, by
specific GENES inherited from your parents.
 You inherit one gene from your MOTHER and one from your
FATHER.
 These genes determine your blood type by causing proteins
called AGGLUTINOGENS to exist on the surface of all of your
red blood cells.
 What are the different blood groups?

 The differences in human blood are due to the presence or

absence of certain protein molecules called ANTIGENS and
ANTIBODIES.
 The antigens are located on the surface of the RBCs and the
antibodies are in the blood plasma.
 Individuals have different types and combinations of these
molecules.
 The blood group you belong to depends on what you have
inherited from your parents
 There are two agglutinins classified as anti-A and anti-B in the serum.
Agglutinugen A and B are present at birth while agglutinins are
demonstrable in about 50% of newly born infants.
 If an individual belongs to group A this indicates that his red blood
cells has agglutinogen A located on its surface. Similarly, all group B
persons have antigen B, all group AB, persons have antigen A and
antigen B or group O persons have neither antigen A nor antigen B.

 When the serum of group A blood was examined, anti-B was found
present and no anti-A. Similarly group B blood contains only anti-A,
group O has both anti-A and anti-B and group AB blood contains
either anti-A or anti-B.
 Parents Possible Not Possible
1. O and O 0 A, B, AB Ten
2. A and O A, O B, AB Different
3. A. and A A, O B, AB Matings
4. B and O B, O A, AB betwee
5. B and B B, O A, AB n Four
6. A and B O, A, B, AB NONE Blood
7. AB and O A, B O, AB Groups
8. AB and A A, B, AB O
9. AB and B A, B, AB O
10. AB and AB A, B, AB O
ABO Blood Grouping System
Why group A blood must never be
given to a group B person?

 Giving someone blood from the wrong ABO

group could be fatal. The anti-A antibodies in
group B attack group A cells and vice versa.
Blood Transfusions

Who can receive blood from whom?

 People with blood group O are called "universal
donors" and people with blood group AB are
called "universal receivers."
People with Blood Group O is universal donors because it
has neither A or B antigens in their RBCs, making them
compatible to all blood type. The absence of antigens will
not trigger an immune response even if the recipient has a
different blood type.

People with blood group AB are called universal receiver

because they can receive RBC from any blood type. They
are also called Universal Plasma donors meaning anyone
can receive type AB Plasma.

If mismatched blood during the transfusion, the body may

fight back and potentially endangers the life of the patient.
Blood Antigen Antibody Can Give Can
Group Blood Receive
To Blood From

AB A and B None AB AB, A, B, O

A A B A and AB A and O
B B A B and AB B and O
O None AB AB, A, B, O O
CLASSIFICATION OF BLOODSTAINS
 Hair Structures
Hair
Human and Animal Hair
 Purposes of examination of hair

1. To determine whether the hair in questioned originated

from an animal or human being and the comparison of
questioned and known hairs.
2. To ascertain whether two or more individuals could have
come into contact or whether one or more individuals could
have come into contact with an object.
 Evidentiary Value of Hair

 The value of hair as evidence in the criminal

cases has been clearly recognized.
 Itis seldom conclusive as evidence, but in
conjunction with other details, has proven to be
an important and essential aid to the investigator.
Collection, Handling and
Preservation of Hair Evidence; Standard
Collection

HEAD HAIRS
Take 50-100 hair strands from different areas of
the head
Combination of cut & plucked strands o
Package separately with proper labels
PUBIC REGION
Do not cut the hair
Comb victim’s pubic region prior to
collecting of standards o30-60 strands.
Hair attached in dry blood or
caught in metal or a crack of
glass – leave hair intact on the
object.
Small objects –wrap it and seal it in
an envelope.
Large objects – wrap the area
containing the hair in paper to
prevent loss of hair during shipment.
 Hair as Evidence

 Hair evidence is one of the most common types of evidence

encountered in criminal investigations.
 During the course of the normal hair growth cycle, hairs are readily lost
from individuals, and these hairs may be transferred during the course
of a criminal activity.
 As the Locard Exchange Principle, it states that any time there is
contact between two surfaces, an exchange of materials will occur.
One of the materials that can be readily collected, identified, and
compared is hair evidence.
 Biology of Hair

 Hair is composed of the protein KERATIN, which is also the primary

component of finger and toe nails.
 Hair is produced from a structure called the HAIR FOLLICLE. Humans
develop hair follicles during fetal development, and no new follicles
are produced after birth.
 Hair color is mostly the result of PIGMENTS, which are chemical
compounds that reflect certain wavelengths of visible light.
 Melanin is the brownish-black pigment. The chemical responsible for
the color of hair. Black and hair differs only on the amount of
melanin. Red hair is thought to be due to iron.
 Hair shape (round or oval) and texture (curly or straight) is
influenced heavily by genes.
 Hair shape (round or oval) and texture (curly or straight) is
influenced heavily by genes.
 The body area (head, arm, leg, back, etc.) from which a hair
originated can be determined by the sample’s length, shape, size,
color, and other physical characteristics.
 NOTE: In order to test hair evidence for DNA, the root must be
present
What are the Kinds of Hair?

Real Hair – long and stiff.

FuzzHair - short, fine at times curly

and wooly.
Parts of Hair

 Root – portion
embedded in the
skin.
 Shaft – portion above
the surface of the skin
 Tip – sometimes
termed point. The
distal end of the
uncut hair shaft.
What are the principal parts of shaft?

1. Cuticle - outer coating composed of overlapping

scales
2. Cortex - protein-rich structure around the medulla
that contains pigment. The intermediate and thickest
layer
3. Medulla - central core (may be absent)
Can we definitely determine gender
through hair examination?

 NO! Male hair is larger in diameter, shorter in length,

wirier in texture.
 Male 1/350 while female is 1/450.
 When hair is as much as six inches in length and has a
split end, this is a good indication that the hair is from
female, but not a positive proof.
Fiber as Evidence
 Fiber

 Fibers are useful in crime scene investigation because

their origins can be identified. A carpet fiber on a
person’s shoe can indicate the individual’s presence at
a crime scene.
 However, fibers are very mobile and can become
airborne, get brushed off or fall from clothing. This
mobility makes timely collection crucial to prevent loss
of material or cross contamination (Deedrick, 2000).
 Locard's Exchange Principle

Wherever he steps, whatever he touches, whatever he leaves, even

unconsciously, will serve as a silent witness against him. Not only his
fingerprints or his footprints, but his hair, the fibers from his clothes, the
glass he breaks, the tool mark he leaves, the paint he scratches, the
blood or semen he deposits or collects.
Fiber as Evidence

The Wayne Williams trial (Atlanta

Child Murders), where fiber evidence
was critical in associating the suspect
with victims and crime scenes.
General Classification of Fiber

1. Natural Fiber. Many different natural fibers that come

from plants and animals are used in the production of
fabric. COTTON fibers are the plant fibers most
commonly used in textile materials. The animal fiber
most frequently used in the production of textile
materials is WOOL, and the most common wool fibers
originate from SHEEP.
2. Synthetic fiber. More than half of all fibers used in the
production of textile materials are synthetic or man-
made. Nylon, rayon, and polyester are all examples of
synthetic fibers.
Test for Textile Fibers
1. Burning or ignition test

i tis a preliminary macroscopic

examination. It determines whether
fiber is animal, or vegetable fiber.
2. Fluorescent test

 frequently used to determine general group

to which a fiber belongs. It is not reliable for
positive identification of fiber.
3. Microscopic examination

Ingeneral, it is the most reliable and

best means of identifying fiber.
 4. Chemical analysis of fibers

 Used the submitted is fairly large, e.g. piece

of cloth, and it supplements and confirms
the result of microscopic examination.
Semen and Seminal Stain
is a measure of how acidic or basic (alkaline) a solution is
is a measure of how acidic or basic (alkaline) a solution is

What is Semen, Seminal Stain and

Seminal Odor?
 Semen It is a body fluid present or produced by male
individuals for fertilization (Mozayani & Noziglia 2006). It is a
viscid fluid with faint yellow color and characteristic odor
called SEMINAL ODOR. Forms gel-like clot immediately. Also, it
consists of spermatozoa suspended in secretion of accessory
glands. Seminal stain is an important biological fluid which
requires identification and characterization in the investigation
of sexual offences like rape, sodomy, bestiality,etc. Normal
semen reference pH range is 7.2 to 7.8.
A measure of how acid or basic (alkaline) solution is.
 What are the parts of the semen?

1. Seminal Fluid. This is the protein rich body fluid

originating from the prostate and seminal vesicles.
 It is alkaline in odor, viscid, gelatinous and sticky.
 Becomes more liquid in character to air for one and half
hour due to enzymatic reaction.
 Liquefies completely in 5-60 minutes.
2. Spermatozoa. It is commonly referred as sperm. This is the male gamete
or sex cell, produced in testis. The semen consists of:
 Spermatozoa (10%)
 Seminal Plasma (90%)
– The seminal plasma is a mixture of secretion derived from the male
accessory reproductive organs. It contains of Citric Acid, Ascorbic Acid,
Lactic Acid, Fructose, potassium Choline Phosphate, free Amino Acids,,
Zinc, Calcium, Spermine, etc.
 Epithelial Cell (< 1%) – forms protective layer
What is a Sperm Cell?

It has pear-shaped head

Behind the head is a short neck
It has a tail about ten times as long
as the head
Do you know that?

 1.5 ml to 3.5 ml is a normal quantity of seminal

fluid per ejaculation.
 There are 400 to 500 million of spermatozoa in a single
ejaculation of a healthy young man.
 There are 50,000 to 350,000 of spermatozoa per
ml
 Is there an ejaculation with NO
spermatozoa?

 YES! Ejaculation with no spermatozoa may occur in the following instances:

1. Males suffering from ASPERMIA
 No spermatozoa at all in the seminal fluid.
2. Males suffering from OLIGOSPERMIA
 Abnormally low sperm counts or with few spermatozoa.
 These diseases can be taken from
 Excessive sexual intercourse
 Testicular diseases
 Chronic venereal diseases
 Is it possible for impotent to commit
rape?

 YES!Seminal constituents on a rape victim

indicate that sexual intercourse occurred BUT
their absence DOES NOT necessarily mean
that a rape did not occur.
Where semen can be found?

 Semen can be found in vaginal and rectal contents as

fresh. Also, it can be found as wet or dried in the hair
and skin of the victim usually around the genitals.
 Moreover, semen may find at the scene of the crime
either on the grass or floor area. Furthermore, dry stains
of semen can be located in the underclothing and bed
clothing.
Glass as Evidence
 What is glass?

 It is amorphous. (A material or solid that lacks a regular, long-range ordered atomic

or molecular structure. )

 It usually composed of oxides like silica, boric oxide, and

phosphorous pentoxide.
 Physical Properties: hard, elastic, brittle, non-conductor of
electricity, density, refractive index, etc.
 Some Types of Glass

1. Flat glass - Used for doors and windows

2. Laminated glass - Used in car windshields. This consists of

two sheets of glass with plastic in between

3. Tempered glass - Used in car side windows. This is

designed to break into tiny pieces
 Glass as Evidence of Crime

 Automobile glass in case of hit and run

 Broken windows as caused by pressure, blow or bullet in case of
robbery.
 Broken bottles, drinking glasses, spectacles found at the scene of an
assault or other crimes of violence, which would suggest examination
of the soles and heels of the suspect for imbedded glass fragments.
How Does Glass Break?

Each force causes

a deformation that
may leave a visible
mark or fracture
the glass. This can
b e u s e d t o
determine the
direction and
amount of force
Radial and Concentric Fracture
TOXICOLOGY
 What is toxicology?

It is a branch of science that treats of poison, their origin, physical,

and chemical properties, physiological action, and treatment of
their noxious effect and methods of detection.
The etymology of toxicology came from ‘’toxico’’ that means poison
and ‘’ology’’ that means study or science. On the other hand,
POISON, from the medical point of view, is a substance that when
introduced into the body and is absorbed through the blood stream
and acting chemically is capable of producing noxious effect.
CLASSIFICATION OF POISON

1. According to Kingdom
Animal - ex. Cantharides
Vegetable - ex. Strychnine
Mineral - ex. Hydrochloric acid
2. According to Chemical Properties
 Inorganic poison - poison without carbon
Volatile - ex. Bromine , Chlorine, And Iodine
Non-volatile - ex. Sulfuric acid
Mineral acid - ex. Hydrochloric acid
Mineral alkalis - ex. Sodium hydroxide
 Organic poison - poison that contains carbon
Volatile - ex. Alcohol, Chloroform
Alkaloid - ex. Strychnine
4. According to Physiological Action
Corrosives – highly irritant poison that cause local destruction of tissues
and characterized by nausea, vomiting, and great local distress. E.g.
Strong acids and alkalis
Irritants – one that produces irritation or inflammation of the mucus
membrane and characterized by vomiting, pain in the abdomen and
purging. E.g. arsenic
Narcotics – one that produce stupor, complete insensibility, or loss of
feeling. E.g. opium, Demerol, and cocaine
Neurotics – one that act chiefly on the nervous system producing
delirium, convulsion and respiration as the outstanding symptoms. E.g.
CO, alcohol, opium, strychnine
Tetanic – substances that act chiefly upon the spinal column
producing such spasmodic and continuous contraction of
muscles as a result of stiffness or immobility of the parts to which
they are attached.
Depressants or Sedatives – agents that retard or depress the
physiological action of an organ. E.g. nicotine and cocaine
Asthenic or exhaustive – agents that produce exhaustion,
marked loss of vital or muscular power. E.g. hydrocyanic acid
According to pharmacological action
Substances characterized by local action - ex. Volatile
oils and skin irritants
Substances characterized by their action after
absorption - ex. Alkaloid C. Heavy metals and
metalloids - ex. Phosphorous, arsenic and mercury
According to methods of isolation
a. Volatile poisons are those isolated by distillation with or
without current or steam. E.g. alcohol, phenol and chloroform
b. Non-volatile poisons are those isolated by extraction with
organic solvents. e.g. alkaloids and organic acid
c. Metallic poisons that are isolated by refluxion. E.g. arsenic
and mercury
d. Substances for which special method of isolation are required
e.g. acids and alkali metals are extracted with water.
 Types of Poisoning
From medical point of view

1. Acute Poisoning – one that there is prompt and marked disturbance

of function or death within a short period of time.
2. Sub-acute poisoning – cases of short duration and extreme violence
that may include symptoms of chronic poisoning.
3. Chronic poisoning – kind of poisoning in which there is gradual
deterioration of function of tissues and may not result in death. Either
taking several doses at long intervals or taking only toxic doses of the
drug produces it.
 From legal point of view

1. Accidental Poisoning – those in which the poison was taken without

intention to cause death. It may be taken by mistake or without
knowing that it is poison.
2. Suicidal poisoning – those in which the victim voluntarily for purpose
of taking his own life took the poison.
3. Homicidal poison – those in which the poison was given willfully,
wantonly and with intent to cause death to the victim.
4. Undetermined – those in which the history is hazy as to how
the poison was obtained and why it was administered
 What is posology?

Itis a branch of science that treats of

the form and quantity of medicine to
be administered within a certain period.
 KINDS OF DOSE

Safe Dose – one that does not cause harmful effect

Toxic or poisonous dose – one that is harmful to both
healthy and sick
Lethal dose – one that kills
Minimum dose – is the smallest amount that will produce the
therapeutic effect without causing harm
Maximum dose – is the largest that will cause no harm but
at the same time produce desired therapeutic effect
 General Treatment of Poisoning

Removal of poison from the stomach. If the poison is taken orally, the removal of the
poison is brought about by:
Inducing vomiting using emetics. Substances or agents that produce vomiting are called
emetics.
Use of stomach pump or stomach tube.
If the poison is applied or instilled – wash
If the poison is injected – ligatures and bleeding

Administration of antidotes.
Mechanical antidote – an agent that removes the poison without changing it or coats the
surface of the organ so that absorption is prevented. Examples include: stomach tubes or
pumps, emetics, cathartics, demulcents and precipitants
What is ANTIDOTE?

 An antidote is a substance used to counteract the effects

of a poison or toxin. Antidotes can neutralize poisons,
prevent their absorption, counteract their effects, or
enhance their elimination from the body. They are critical
in medical treatments for various types of poisoning,
including drug overdoses, chemical exposures, and
envenomation's (bites or stings from venomous animals).
Classes of emetics:
 Local emetic – produce their effects by their irritation of the terminal nerve filaments of
the pharynx, esophagus or stomach
 System or general emetics – produce their effects through the medium of circulation
Cathartic – agents that produce intestinal evacuation
Demulcents – substances that soothe and protect the part which they are applied.
Precipitants – these are substances that prevent absorption of poisons by
precipitating them and rendering them insoluble.
Chemical antidote – substance that make the poison harmless by chemically
altering it. Physiological antidote – sometimes called “antagonist”. An agent that
acts upon the system so as to counteract the effect of poison. It merely masks the
symptoms produced.
 EVIDENCE OF POISONING IN THE
LIVING BODY

The evidence of poisoning will depend upon whether the poisoning is

acute or chronic. In acute poisoning the symptoms appear suddenly while
the individual is in good health. The person is usually affected with a group
of symptoms of definite characteristics out of consonance with his
previous state of health. In chronic poisoning, the onset of symptoms is
more gradual and insidious due to the small quantity of poison that has
been administered on such occasion since the intention of the prisoner is
to kill his victim slowly in order to avert suspicion.
Thank you for listening!