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Questions and Answers
What type of evidence is hearsay evidence primarily based on?
Which of the following is NOT a form of scientific evidence?
What percentage of blood is composed of solid components?
Which type of witness provides opinions based on special skills?
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What constitutes the liquid portion of blood?
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Which type of evidence may include conducting experiments to establish a fact?
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Which of the following statements about suspects is accurate?
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Which of these is a characteristic of an ordinary witness?
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What is formed inside the barrel of a gun if it has been fired?
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Which method is recommended for examining powder particles that are deeply embedded?
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What color indicates the presence of nitrate when using diphenylamine in testing?
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Which characteristic does NOT describe hair?
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What type of hair is typically described as long and stiff?
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Which explosive characteristic is based on its functionality?
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What is a major benefit of hair examination in criminal investigations?
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What is the black substance formed by combustion referred to as?
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What is the main component of plasma?
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Which test is used for the preliminary detection of blood?
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What substance can be added to blood for preservation at room temperature?
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What is the purpose of the precipitin test?
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Which blood group contains both antigens A and B?
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In which scenario would dried blood NOT typically be collected?
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What is an example of a confirmatory test for blood?
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What is the correct antigen and antibody combination for blood group B?
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What characterizes the medullary index for human hair?
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How can dyed hair be distinguished from natural hair under a microscope?
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Which is NOT a characteristic of the cuticle observed in hair?
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What is a distinguishing feature of animal hair compared to human hair?
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Which aspect of hair contributes essential information for comparison between individuals?
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What feature of the medulla is characteristic of human hair?
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What characteristic does the tip of an uncut hair contain?
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Which region is indicated as having more mature hair characteristics?
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What characteristic distinguishes beard hair from other types of hair?
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Which type of hair is described as having an irregular shape and a bleached appearance?
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What distinguishes pubic hair from auxiliary hair?
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Which test is considered the most reliable method for identifying fibers?
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What happens to the pigment in hair as an individual ages?
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What is a common feature of infant hairs?
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What differentiates natural fibers from synthetic fibers?
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Which chemical test involves staining fibers to determine their composition?
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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.