Legal Evidence Types

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Questions and Answers

What type of evidence is hearsay evidence primarily based on?

Direct observation by the witness

Written documentation from the witness

Repetition of what others have said (correct)

Experiments conducted by the witness

Which of the following is NOT a form of scientific evidence?

Hearsay Evidence (correct)

Testimonial Evidence

Real or Autoptic Evidence

Documentary Evidence

What percentage of blood is composed of solid components?

45% (correct)

30%

55%

60%

Which type of witness provides opinions based on special skills?

Expert Witness Signup and view all the answers

What constitutes the liquid portion of blood?

Plasma Signup and view all the answers

Which type of evidence may include conducting experiments to establish a fact?

Experimental Evidence Signup and view all the answers

Which of the following statements about suspects is accurate?

Suspects are individuals with reasonable grounds for guilt. Signup and view all the answers

Which of these is a characteristic of an ordinary witness?

States facts without personal opinion Signup and view all the answers

What is formed inside the barrel of a gun if it has been fired?

Iron salts Signup and view all the answers

Which method is recommended for examining powder particles that are deeply embedded?

Walker's Test Signup and view all the answers

What color indicates the presence of nitrate when using diphenylamine in testing?

Yellow-green Signup and view all the answers

Which characteristic does NOT describe hair?

Completely round structure Signup and view all the answers

What type of hair is typically described as long and stiff?

Real hair Signup and view all the answers

Which explosive characteristic is based on its functionality?

Rate of decomposition Signup and view all the answers

What is a major benefit of hair examination in criminal investigations?

Uniqueness among individuals Signup and view all the answers

What is the black substance formed by combustion referred to as?

Soot Signup and view all the answers

What is the main component of plasma?

Yellowish fluid Signup and view all the answers

Which test is used for the preliminary detection of blood?

Benzidine Test Signup and view all the answers

What substance can be added to blood for preservation at room temperature?

Sodium Fluoride Signup and view all the answers

What is the purpose of the precipitin test?

Determining the origin of blood Signup and view all the answers

Which blood group contains both antigens A and B?

Group AB Signup and view all the answers

In which scenario would dried blood NOT typically be collected?

From indoor carpets Signup and view all the answers

What is an example of a confirmatory test for blood?

Microscopic Test Signup and view all the answers

What is the correct antigen and antibody combination for blood group B?

Antigen B and Anti A Signup and view all the answers

What characterizes the medullary index for human hair?

Less than 0.5 Signup and view all the answers

How can dyed hair be distinguished from natural hair under a microscope?

Dyed hair has a constant color tone. Signup and view all the answers

Which is NOT a characteristic of the cuticle observed in hair?

Presence of dye Signup and view all the answers

What is a distinguishing feature of animal hair compared to human hair?

Always has a medulla Signup and view all the answers

Which aspect of hair contributes essential information for comparison between individuals?

Color of the cortex granules Signup and view all the answers

What feature of the medulla is characteristic of human hair?

Narrow medulla less than 0.5 Signup and view all the answers

What characteristic does the tip of an uncut hair contain?

Tip structure Signup and view all the answers

Which region is indicated as having more mature hair characteristics?

Scalp hair Signup and view all the answers

What characteristic distinguishes beard hair from other types of hair?

It is coarse, curved, and often triangular in cross section. Signup and view all the answers

Which type of hair is described as having an irregular shape and a bleached appearance?

Auxiliary Hair Signup and view all the answers

What distinguishes pubic hair from auxiliary hair?

Pubic hair is wiry, coarser, and has more constriction and twist. Signup and view all the answers

Which test is considered the most reliable method for identifying fibers?

Microscopic test Signup and view all the answers

What happens to the pigment in hair as an individual ages?

The pigment disappears or starts to disappear. Signup and view all the answers

What is a common feature of infant hairs?

They are fine, short, and have rudimentary character. Signup and view all the answers

What differentiates natural fibers from synthetic fibers?

Natural fibers come from plants or animals. Signup and view all the answers

Which chemical test involves staining fibers to determine their composition?

Chemical test Signup and view all the answers

Study Notes

Hearsay Evidence

Hearsay evidence is a statement made by a witness based on what they heard from someone else, not their personal knowledge.
Generally inadmissible in court, with exceptions like declarations against interest, dying declarations, reputation, and public records.

Scientific Evidence

Based on scientific knowledge, principles, and techniques.
Types include:
Real or Autoptic Evidence
- Evidence perceived by the senses (sight, hearing, taste, smell, touch).
Testimonial Evidence
- Expert witness gives their professional opinion on the case.
Experimental Evidence
- Expert performs experiments to support a fact during the case.
Documentary Evidence
- Written evidence, presented by an expert, relevant to a case.

Witness

A person who provides information about an incident or person.
Can be:
Ordinary Witness
- Testifies to facts, not opinions or conclusions.
Expert Witness
- Possesses specialized knowledge or skill.
Eye Witness
- Saw the event in question firsthand.

Suspect

A person whose guilt is a reasonable possibility based on the available evidence.

Blood and Bloodstains

Complex mixture of cells, enzymes, proteins, and inorganic substances.

Composition of Blood

Solid portion (45%):
- Red blood cells (erythrocytes)
- White blood cells (leukocytes)
- Blood platelets (thrombocytes)
Liquid portion (55%):
- Plasma: Yellowish fluid containing blood corpuscles.

Serum

Straw-yellow liquid formed when blood clots and separates.

Problems in the Study of Blood

Locating blood evidence.
Preserving blood evidence: requires special handling to prevent decomposition.
- Sodium fluoride can preserve blood for a week at room temperature or in a refrigerator.

Blood Collection

Fluid Blood:
- Victims of violent crimes
- Parents and children for disputed parentage
Dried Blood:
- Smooth surfaces (walls, floors)
- Hard surfaces (weapons)
- Glass and tile surfaces
- Bulky objects (furniture)
- Clothing
- Soil

Blood Tests

Preliminary Test: Determines if the stain contains blood
- Benzidine test (Intense blue color)
- Phenolpthalein test (Deep pink color)
- Guaiacum test (Beautiful blue)
- Leucomalachite Green test (Bluish Green)
- Luminol test
Confirmatory test : Confirms the presence of blood
- Microscopic Test
- Microchemical Test
- Spectroscopic Test
Precipitin Test: Determines if the blood is human or animal origin.
Blood Groupings:
- A-B-O system categorizes blood based on antigens and antibodies using the four blood groups: O, A, B, and AB.

Hair and Textile Fibers

Hair examination is an older forensic technique used in many investigations due to hair's resistance to decomposition.

Hair

Specialized epithelial outgrowth of the skin, found everywhere except the palms of the hands and soles of the feet.
Not completely round, can be oval or flattened.
Width can vary.

Kinds of Hair (Among mammals, including humans)

Real Hair: Long and stiff.
Fuzz Hair: Short, fine, curly.

Parts of Hair

Root: Embedded in the skin.
Shaft: Portion above the skin, the most distinctive part.
Tip: Distal end of an uncut hair.

Microscopic Examination of Human Hair

Color: Melanin is the pigment responsible for hair color.
Length: Measured directly.
Characteristics: Width, tip, cut style, root condition.
Cuticle: Size, shape, and irregularity of scales.
Cortex: Pigment granules provide color, shape, and distribution help with comparisons.
Dye detection: Dyed hair may have a dull appearance under a microscope.
Curling detection: Natural or artificial curl is often visible under a microscope.
Medulla: Contains a central core of the hair shaft.
- Medullary Index: Ratio of medulla diameter to hair diameter (0.5 or less = human hair, 0.5 = cow/horse, greater than 0.5 = other animals).

Comparative Features Between Human and Animal Hair

Human Hair:
- Medullary index (MI) is less than 0.5.
- Medulla may not be present.
- Scales are fine and overlap more than 4/3.
- Pigment granules are fine.
Animal Hair:
- MI is more than 0.5.
- Medulla is always present.
- Scales are coarse and overlap less than 1/2.
- Pigment granules are coarse.

Determining the Region of the Body from which Human Hair Originated

Scalp Hair: More mature.
Beard Hair: Coarse, curved, stiff, often triangular.
Eyebrows, eyelids, nose, ears: Short, stubby, wide medulla.
Trunk Hair: Vary in thickness, somewhat similar to scalp hair, fine and long tip ends.
Limb Hair: Similar to trunk hair, may be shorter and less coarse.
Auxiliary Hair (Armpit): Long, unevenly distributed pigment, may appear bleached.
Pubic Hair: Similar to axillary hair, but coarse, not bleached, wiry, twisted, broad medulla, often broken ends.

Approximate Age Determination Using Hair

Infant hair: Fine, short, fine pigment, rudimentary.
Childhood hair: Finer and more immature than adult hair, but cannot be definitively distinguished from adult hair.
Adolescent hair: Similar to adult hair.
Adult hair: May show signs of pigment reduction or loss.
- Premature gray or white hair in young people is possible, but not in body hair.

Textile Fibers

Fibers converted into yarn.

Yarn

Fibers twisted together like a thread.

Classification of Textile Fibers

Natural: Cotton, wool, silk, linen.
Synthetic or Artificial: Nylon, polyester, acrylic.

Tests for Fibers

Burning Test: Determines if fiber is mineral, animal, or vegetable.
Fluorescence Test: Determines the general fiber group - not reliable for positive identification.
Microscopic Test: Most reliable method for fiber identification.
Chemical Test:
- Staining test: Staining with picric acid, Millon's reagent, stannic chloride, or iodine solution.

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Description

This quiz covers the various types of legal evidence, including hearsay, scientific evidence, and the roles of different types of witnesses. Explore the nuances of admissible statements and the scientific basis for evidence in court cases. Test your knowledge of legal principles and standards related to evidence.