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    Criminalistics vs. Criminology

    Criminalistics: Scientific examination of physical evidence for legal purposes. AKA Forensic Sciences. Criminology includes psychological angle, looking at motives, traits, behaviors etc.

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    Basic services in a crime lab

    Physical science, biology, fingerprints, firearms, drug chemistry, document examination, photography

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    Prongs of Daubert

    Testability, General acceptance, Peer review, Known or potential error rate, Maintenance of standards and controls

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    Locard exchange principle

    Whenever two objects come into contact with each other, traces of each are exchanged.

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    Direct evidence

    Evidence that establishes fact (eyewitness, confession)

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    Circumstantial evidence

    Evidence that relies on an inference

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    Testimonial evidence

    Testimony under oath

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    Physical evidence

    Object or material that's relevant in a crime. Can be transient, pattern, conditional, transfer, or associative.

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    Transient evidence

    Temporary, easily lost or changed evidence. e.g. odor, temperature, marking

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    Pattern evidence

    Evidence produced by direct contact between persons or objects.

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    Conditional evidence

    Produced by a specific event or action. e.g. Light, smoke, fire, location

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    Transfer evidence

    Produced by contact between persons and/or objects

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    Members of a crime scene team

    First police officer on scene, medics(if necessary), investigator(s), medical examiner(if necessary, photographer and/or field evidence technician, lab experts.

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    What are the duties of the first office on scene?

    ADAPT -- Assess the scene, Detain witness, Arrest perpetrator, Protect scene, Take notes

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    What is the role of a homicide detective?

    Document crime scene, interview original patrol officer, examine crime scene with crime scene investigator, pass on necessary info to assisting detectives.

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    What does a Medicolegal Death Invesitgator do?

    Confirm and pronounce death, photograph scene and body, identify deceased if possible, document(sketch) and evaluate body, collect evidence, reconstruct death even, maintain jurisdiction over body, ensure safe conveyance of body, assist family

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    Frye v. United States (1923)

    Scientific evidence is allowed into the courtroom if it was generally accepted in the scientific community

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    Daubert v. Dow (1993)

    - Admissibility is determined by...
    -whether the theory/technique can be tested, Whether the rate of error is acceptable(accurate and reliable), Whether the method enjoys widespread acceptance, and Whether opinion is relevant to the issue

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    Probative Value

    The level at which evidence provides proof of the crime

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    Associative Value

    The value used to place a suspect at a crime

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    Trace Evidence

    Any small pieces of material, man-made or naturally occurring (animal, plant, or mineral) - including hair, fibers, soil, sand, plant material

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    From hair, you can determine...

    Human or animal
    Race
    Origin
    Manner in which hair was removed
    Treated hair
    Drugs ingested

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    Hair Shaft

    Part of the hair that sticks out of the skin

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    Hari Root

    Lies below the epidermis

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    Hair Follicle

    Structure from which the hair grows

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    Hair shaft is composed of...

    Cuticle, Cortex, and Medella

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    Hair Cuticle

    Outside covering, made of overlapping scales, covered with scales

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    Hair Cuticle Scales

    Differ between species, are named based on appearance.
    - Imbricate (HUMAN): flattened
    - Coronal: crown shaped
    - Spinous: petal like

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    Cortical Fusi

    Air spaces, usually found near the root but may be found throughout the hair shaft

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    Medulla

    Inside layer running down the center of the cortex (NOT always present!)

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    Medulla Types

    - Continuous
    - Intermittent or Interrupted
    - Fragmented
    - Absent (not there)

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    Medullary Index

    Determined by measuring the diameter of the medulla and dividing it by the diameter of the hair (Humans, generally less than 1/3 // Animals, greater than 1/2)

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    Human vs. Animal hair

    -Human hairs generally more consistent in color/pigmentation throughout length of shaft, whereas animal hairs may exhibit radical color changes in a short distance called banding
    -Medulla, when present in human hairs, is generally less than 1/3 diameter of hair shaft. Medulla in animal hairs generally occupies an area of greater than 1/2 diameter of hair shaft.

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    Anagen

    Hair that is growing, lasting up to 5 years

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    Catagen

    Hair at rest

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    Telogen

    Hair that is dying

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    What can't be determined by hair?

    Sex, Age (Only by DNA analysis if root tissue is present)

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    Probative value of soil

    - As a result, the statistical probability of a given sample having properties similar to another is very small
    - Evidential value of soil is usually excellent

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    Significance of plant material at scene

    1. Plant remains can be found almost everywhere
    2. Offers macroscopic and microscopic evidence (pieces of wood, seeds, fruits, leaves, twigs, plant hairs, microscopic pollen, spores, algal cells)
    3. Structure allows identification of the plant and allows gathering of other useful info (season, location, where a body could be buried, how long it's been buried, if a suspect was at the scene)

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    Double Helix

    - Two coiled DNA strands
    - Composed of nucleotides

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    Nucleotides

    Unit containing a sugar molecule (deoxyribose), a phosphate group and a nitrogen-containing base

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    4 Bases of DNA

    1. Adenine (pairs with Thymine)
    2. Cytosine (pairs with Guanine)
    3. Guanine (pairs with Cytosine)
    4. Thymine (pairs with Adenine)

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    DNA can be found in...

    Can be found in all body cells- blood, semen, saliva, urine, hair, teeth, bone, tissue

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    DNA is most abundant in our...

    Buccal (Cheek) Cells

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    Human Genome is made up of...

    23 pairs of Chromosomes

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    Use of DNA Profiling

    - To identify potential suspects
    - To exonerate individuals
    - To identify crime and causality victims
    - To establish paternity
    - To match organ donors

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    DNA Typing - Fingerprinting: RFLP

    Restriction Fragment Length Polymorphism

    Steps:
    Isolation -- separates DNA from cell
    Cutting -- using a restriction enzyme to make shorter base strands
    Sorting -- by size, using electrophoresis
    Analyzing -- the specific alleles for identification
    Takes ~10 weeks

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    DNA Typing - Fingerprinting: PCR

    Polymerase Chain Reaction

    Technique for making many copies of a defined segment of a DNA molecule.
    Steps:
    Denaturation -- separating strands of DNA
    Annealing -- Attaching primers
    Extension -- Adding the dNTPs and duplicating the DNA

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    DNA Typing - Fingerprinting: STR

    Short Tandem Repeats

    Latest DNA Typing method
    STRs are locations on chromosome that contain short sequences of 3 to 7 bases that repeat themselves with the DNA molecule.
    Higher discrimination than RFLP, less time, smaller sample size, less susceptible to degradation.
    Each person has two STR types each gene --one inherited from each parent.

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    DNA Typing - Fingerprinting: Mitochondrial

    Use of material DNA in the mitochondria.

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    DNA Typing - Fingerprinting: Y Chromosomes

    Only with male inheritance

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    Electrophoresis

    method of separating serum proteins by electrical charge

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    Short Tandem Repeats (STR)

    - STR is the latest method of DNA typing.
    - STR's are locations (loci) on the chromosome that contain short sequences of 3 to 7 bases that repeat themselves with the DNA molecule.

    This method's advantages include a higher discrimination than RFLP, less time, smaller sample size, and less susceptible to degradation.

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    Electropherogram

    The visualization of which variant of STR you have

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    3 Possible Outcomes of DNA Testing

    Inclusion, Exclusion, and Inconclusive

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    FBI's CODIS Database

    "Combined DNA Information System"
    *Requires >4 RFLP markers and or 13 core STR markers

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    Nuclear DNA

    - Found in the nucleus
    - Constitutes 23 pair of chromosomes, inherited from both parents
    - Each cell contains only 1 nuclei

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    Mitochondrial DNA

    - Found in mitochondria
    - Inherited from the mother
    - Each cell consists of thousands of mitochondria
    - Can be found in skeletal remains

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    How many genes are involved in mitochondrial energy generation?

    37

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    Blood Droplet Characteristics

    - A blood droplet will remain spherical in space until it drops onto a surface
    - Once a blood droplet impacts a surface, a bloodstain is formed
    - A droplet falling from the same hight, hitting the same surface at the same angle, will produce a stain with the same basic shape

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    Blood Droplet Volume is directly dependent upon...

    the surface or orifice from which it orginates

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    Shape & Size of Bloodspot depends mostly on...

    nature of the target surface:
    - texture (rough or smooth)
    - porous or non-porous

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    There is little change in a spot diameter of a bloodspot beyond...

    a fall distance of 1.2 m

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    Blood Stain Transfer

    When a bloody object comes into contact with a surface and leaves a patterned blood image on the surface.

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    Directionality

    Relates to the direction a drop of blood traveled in space from its point of origin

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    Swipe

    Wet blood is transferred to a surface which did not first have blood on it

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    Wipe

    A non-blood bearing object moves through a wet bloodstain, altering the appearance of the original stain

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    Formula to determine angle of blood droplets:

    Width / length = sine of the impact angle

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    Angle of Impact:

    The more acute the angle of impact, the more elongated the stain
    90 degree angles are perfectly round with 80 degree angles taking on more of an elliptical shape
    At about 30 degrees, the stain will begin to produce a tail
    The pointed end of the blood stain FACES the direction the stain is traveling

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    Point of Origin

    Point of Origin - The point of origin is the spot where the "blow" occurred. It is determined by drawing a line from the area of intersection straight up to where the angle of impact would intersect. It may be established at the scene with use of strings.
    - It is the 3 dimensional location from which the blood spatter occurred

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    Jan Garavaglia

    'Dr. G.' Medical Examiner in Casey Anthony case

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    Bugs help us because...

    By using their life cycles we can estimate time of death.

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    Dr. Neal Haskell

    Former entomologist. Worked as Forensic Entomology Consultant throughout US. Wrote etymology report attached to autopsy report. Determined coffin flies of back of a car in Anthony case

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    Chromatography

    Method of pulling chemical mixture apart, into their component compounds.

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    Gas Chromatography Mass Spectrometer

    Drug test. Main instrument in toxicology lab

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    Gender differences in bones

    - The pelvis of the female is wider
    - Males have a narrow subpubic angle and a narrow pubic bone body

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    Best bone to determine race?

    Skull

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    Best bone to determine height?

    Femur

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    Best bone to determine age?

    Teeth

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    An experienced Anthropologist can place skulls into what 3 groups?

    - Caucasian (European, Middle Eastern, Indian)
    - Negroid (African, Aborigine, Melanesian)
    - Mongoloid (Asian, Native American, Polynesian)

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    Teeth are often used for body ID because?

    1. Hardest substance in the body
    2. Unique to an individual
    3. There is usually a good record of our teeth
    4. Sometimes pulp remains in tooth - good source of DNA

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    To prove a poisoning case...

    - Prove a crime was committed
    - Motive
    - Intent
    - Access to poison
    - Access to victim
    - Death was caused by poison
    - Death was homicidal

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    Medical Examiner's responsibilities

    Identify deceased, establish time and date of death, determine medical cause of death, determine mechanism of death, classify manner of death

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    Cause of Death

    injury or disease that resulted in death

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    Mechanism of death

    Physical reason person died

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    Manner of death

    Natural, accidental, suicide, homicide, undetermined

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    Physical Science Unit in a crime lab is comprised of...

    Chemistry, physics, geology

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    Biology Unit in a crime lab looks at...

    biological screening, DNA, blood spatter, etc.

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    Fourth Amendment

    Protects Americans against unreasonable searches and seizures. No soldier, Gov agent, or police can search your home without a search warrant.

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    Fifth Amendment

    A constantutional amendment designed to protect the rights of persons accused of crimes, including protection against double jeopardy, self-incrimination, and punishment without due process of law.

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    Miranda rights

    Statements that must be made by the police informing a suspect of his or her constitutional rights protected by the Fifth Amendment, including the right to an attorney provided by the court if the suspect cannot afford one.

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    In order for evidence to be admissible, it must be:

    Probative & Material

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    Chain of Custody

    A written record of all people who have had possession of an item of evidence.

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    Chain of custody is maintained by...

    -Evidence container must be marked for identification
    -Collector's initial should be placed on the seal
    -If evidence is turned over to another person, the transfer must be recorded.

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    Primary Crime Scene

    Crime occurred at this scene

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    Secondary Crime Scene

    Body/evidence found, but crime didn't occur there

    Fingerprint -- Arch

    No deltas or cores.

    Fingerprint -- Loop

    Have one delta

    Fingerprint -- Whorl

    Have 2 deltas

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    IAFIS

    Integrated Automated Fingerprint Identification System (FBI's). Police forces can submit samples to be compared to those on this computerized database

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    AFIS

    Automated Fingerprint Identification System. Computerized fingerprint search systems match prints by comparing the position of which two types of minutia?

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    Class Characteristics

    Properties of evidence that can be associated only with a group and never with a single source. E.g. Rifling

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    Individual Characteristics

    Marks or features produced by random imperfections or irregularities of tool surfaces. These characteristics can be used to individually associate tool to tool mark. E.g. Manufacture, wear from use, wear from abuse.

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    Visible Prints

    Visible

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    Plastic Prints

    Impression left on soft material like putty, wax, soap, dust

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    Latent Prints

    Not visible to human eye. Consist of natural secretions of human skin and require treatment to cause them to become visible

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    CODIS

    -Combined DNA Index System.
    -Used for linking crimes and unsolved cases with repeat offenders.
    -Requires more than 4 RFLP markers and/or 13 core STR markers.

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    Field Drug Tests

    Presumptive Tests

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    Lab Drug Tests

    Conclusive Tests

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    Forensic Anthropologist...

    Provides basic identification of skeletonized or badly decomposed remains.

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    From a whole bone or part of a bone, the scientist may be able to determine:

    Age, sex, race, heigh, previous trauma, body type, possible cause of death.

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    Responsibility of an entomologist

    Determining time of death

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    Human decomposition stages

    -Fresh--from moment of death to visible bloating
    -Bloated--begin when the abdomen starts to inflate
    -Decay--begins when the skins breaks and the gasses escape. Body deflates.
    -Post-decayโ€”when only 20% or less of the body weight remains
    -Skeletal--when only bones and hair remain

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    How time of death is determined from insect activity?

    After death, body attracts insects; time is tracked by metamorphosis/life cycle of bug

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    Forensic Document Examiner

    ACE -- Acronym for Doc. Examiner. Analyzes/compares questioned documents with real ones to verify authenticity

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    Forensic Linguists...

    Look at way document is written.
    -Language that is used can help to establish the writer's age, gender, ethnicity, level of education, professional training, and ideology.

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    Ink is analyzed by...

    Chromatography.
    Types
    -Gas Chromatography
    -HPLC--high-performance liquid chromatography
    -TLC--thin-layer chromatography
    -Paper Chromatography

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    Visible computer data

    Visible

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    Latent Computer Data

    Not apparent

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