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MEDJUR - WEEK 2, Forensic Serology - The examination and analysis of body…

- - - - D. Locard's Principle - whenever “there is an interaction between the criminal suspect and the victim in the crime scene, trace evidence will be taken away or be left behind in the crime scene.
        
        F. Methods of Identification - Covers by comparison and, by conclusion.
        
        Comparison - comparing evidence with a known sample
        
        Exclusion - given a set of data such as a population list, if almost all is accounted for then the ones who are missing must be the unidentified person.
        2a. This is prone to error, there is always a level of uncertainty.
        
        Methods in Identification of Laymen - Usually involves the process of description of the characteristics of the unknown.
        
        Applicable to the Living -
        
        Hair growth
        
        Clothing
        
        Frequent Places Visited
        
        Profession
        
        Body Ornamentation
        
        Applicable to both the living and the dead
        
        Occupational Marks
        
        Race
        
        Stature
        
        Tattoo Marks
        
        Weight
        
        Deformity
        
        Birthmarks
        
        Injuries
        
        Scars
        
        Tribal Marks
        
        Sexual Organ
        
        H. Limitations of Physical Descriptions
        
        Portrait Parle - A verbal, accurate and picturesque description of the person identified. Considered the endpoint of a witness description. Originally, a french term referring to a picture of a suspect in both front and profile views.
        
        1 more item...
        
        Limitations of Light -
        
        Clearest moonlight - If Known person, 16-17 yards
        
        Clearest Starlight - 10-13 Yards
        
        Broad Daylight -
        3a. Known Person - 100 yards, if person is known
        3b. Stranger - 25 yards, if person is a stranger
        
        Flash from a firearm - letters of 2 inches, can be seen a distance from 2 feet
        
        G. Characteristics which may not easily be changed -
        
        Mental Memory
        
        Speech
        
        Gait
        
        Mannerism
        
        Hands and feet
        
        Complexion
        
        Changes in Eye Characterisitcs
        
        Facies
        
        Handedness
        
        Degree of nutrition
        
        Techniques in Identification which require specialized training
        
        Importance and Scope -
        
        Cornerstone of forensic science.
        
        Trace evidence necessarily includes DNA evidence and serologic evidence
      - Law of Multiplicity of Evidence in Identification - The greater the number of points of similarities and dissimilarities of the two persons compared; the greater the probability of the conclusion to be correct.
        
        Applies in fingerprint analysis, DNA analysis and other techniques
- - - - Confirmatory Tests -
        
        Crystal Test - Formation of haemochrmagen cyrstal. This can be either the Teichmann or the Takayama test
        
        Microscopic Analysis - Rhombic or diamond shaped crystals are seen on microscopy after application of the crystal test
        
        Determination of Species -
        
        Serum Protein Analysis
        
        Nonserum Protein Analysis
        
        Serum Protein Analysis -
        
        Materials Used - Albumin, Alpha 1/2 globulins, Beta Globulins, Gamma Globulins (Most useful, or antibodies)
        
        Tests Used - Ring Precipitin Tests, Ouchterlony double Diffusion tests, Crossed over electrophoresis
        
        NonSerum Protein Analysis - Uses the antihuman hemoglobin antibody - In this test antibodies that target human blood are mixed with human blood. A positive result would cause the red blood cells to burst.
      - Catalytic Color Test - This includes the following:
        
        Benzidine Test (Adler Test) - No longer in use because it is carcinogenic or cancer causing to the examiner
        
        Phenophthalein Test ( Kastle Mayer) (specific) - 1:100,000 sensitivity
        
        O-Tolidine - Similar to Benzidine test but modified to prevent carcinogenicity
        
        Tetramethylbenzidine (most sensitive)
        
        Leucomalachite Green (specific) - 1:300,000 sensitivity
        
        Chemiluminescence - Process by which light is emitted as a product of chemical reaction
        
        Fluorescence - When a chemical substance is exposed to a certain wavelength of light and light is emitted as a by-product. Such as Fluorescein.
        
        Excitation Length - 520mm
        
        Emission Wavelength - 480mm
        
        Advantages - Primarily used to show the extent of blood for purposes of documentation.
        
        When blood has been cleaned or not clearly visible, both techniques can still show the blood pattern.
- - - - How Used - A minimum of 8 Points of comparison are needed for a positive match.
        
        Evidentiary Prints - Partial prints usually. Then matched with the ones on file.
  - - - Development - Refers to the process of rendering a latent print visible, otherwise known as enhancement or visualization.
        
        Forms of Development - Dependent on the composition of the residue of the latent print:
        
        Primary – eccrine /sweat glands which is composed of water, salts such as sodium chloride, some amino acids and simple sugars
        
        Secondary – apocrine residue (since no oil gland in hands) which is composed of oily residue primarily from transfer of such residue when the hand brushes along the face and the body.
    - - Chemical methods -
        
        Ag NO3 – reacts with the chloride ion of sweat
        
        Ninhydrin – reacts with the protein or amino acids in sweat
        
        PD / Physical Developer – 2nd step to silver nitrtate reacts with chloride ion of swear
        
        Physical Methods - These do not involve any chemical reaction and takes advantage of the powders affinity to water, which is the primary component of sweat.
        
        Powder Dusting -
        
        Magnabrush - Differs from powder dusting in that particles are magnetic, thus, dusting is avoided by moving a magnet over the affected area
        
        Small Particle Reagent - Used for Wet surfaces
        
        Special Illumination - Use of specialized optics, lasers, oblique lighting and special filters. Spray substance, and then use blue light --> pictures.
        
        Advantages - Used primarily to target fingerprints situated along historical monuments or other surfaces that cannot be taken back to he lab for analysis.
        
        Disadvantages -
        
        Small particle Reagent - has a chance of smudging the prints
        
        Absorbent - If the surface is absorbent may be unusable. Thus need for chemical methods.
        
        Fuming Methods -
        
        Iodine Fuming – reacts with the carbohydrates in sweat
        
        Cyanoacrylate Ester – also known as super glue or mighty bond in the Philippines
        
        Disadvantages - Prevents doing further analysis like DNA, as the chemicals used contaminate the sample e.g., destroy the DNA, etc.,
        
        Current Fingerprint Analysis Tools - Similar basis for Biometric data.
        
        Use of Automated Fingerprint Identification Tool (AFITS??) - Scan of the print, matches with database.
        1a. Biometric - Minutia points - Munita Map - Data Stream
        
        Issue - Machine cannot determine orientation of the fingerprint, thus matches any value with that particular data stream. This is why expert witnesses needed.
- - - - Video Superimposition - Used to determine whether the skull of that person is in the photogrpah, a mode of facial reconstruction.
      - Craniofacial Reconstruction - Technique developed to render a facsimile of how the skeletal remains might have appeared in life. This is based on soft tissue depth on various locations in the skull.
    - - Sex - Involves comparison of relevant bones that differ from male and female:
        
        Pelvis
        
        Skull
        
        Sternum
        
        Femur
        
        Humerus
        
        Age - Compares the ff: factors
        
        Size of the Bones
        
        Appearance of the Ossification Centers
        
        Union of Bones and Epiphyses
        
        Importance of Determination of Age & Sex -
        
        Crimes - Certain crimes are determined by age and sex e.g., seduction, infanticide
        
        Capacity - Determined by age. This covers right to marry.