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Forensic Science -Debatable -Is the application of science to those criminal and civil laws that are enforced by police agencies in a criminal justice.

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Presentation on theme: "Forensic Science -Debatable -Is the application of science to those criminal and civil laws that are enforced by police agencies in a criminal justice."— Presentation transcript:

1 Forensic Science -Debatable -Is the application of science to those criminal and civil laws that are enforced by police agencies in a criminal justice system. -Debatable -Is the application of science to those criminal and civil laws that are enforced by police agencies in a criminal justice system.

2 Important People Mathieu Orfila (1787-1853) -Father of forensic toxicology -Spanish -Taught medicine in France -1814-published a report on the detection of poisons and their effects on animals. Alphonse Bertillon (1853-1914) -Father of original identification. -Developed the science of anthropometry-a systematic procedure of taking a series of body measurements as a means of distinguishing an individual from another. -Replaced by fingerprinting. Francis Galton (1822-1911) -1 st definite study of fingerprints and developed a methodology of classifying them for filing. -1892-Wrote book on fingerprinting.

3 Important People Cont. Leone Lattes (1887-1954) -Discovered the ABO blood typing -1915-Developed a procedure to determine blood group of dried blood. Calvin Goddard (1891-1955) -U.S. Army Colonel -Began the use of comparison microscope to match fired and test fired bullets from a gun--Ballistics Albert S. Osborn (1858-1946) -Wrote questioned documents (1910) -Developed the fundamental principles of document examination which was accepted by the courts.

4 Important People Cont. Hans Gross (1847-1915)-Prosecutor and judge in Australia -Spent years developing and studying the principles behind a criminal investigation. -Incorporated fields of microscopy, chemistry, physics, minerology, zoology, botany, and fingerprinting. Edmond Locard (1877-1966) -French -Developed the “Locard’s Principle” “With every contact people have, they leave something behind.”

5 The Scientific Method and The Criminal Investigation Scientific Method 1- State the problem 2-Form a hypothesis 3-Collect data Observing and experimenting 4-Interpret the data 5-If data supports hypothesis, collect more data 6-Draw conclusions Criminal Investigation -What crime was committed and in what jurisdiction? -Hypothesize as to possible suspects based on information gathered from witnesses, physical evidence at the crime scene, and motive (if determined) -Seek out pertinent records -Review and evaluate the evidence so far available relative of making a case-for or against each suspect -Seek additional evidence that will help support and prove your case -Arrest suspect and continue seeking evidence to support or refute the guilt of defendant The answer is always there, it is just a matter of asking the right questions.

6 Crime Scene Physical Evidence: Only and all objects that can establish that a crime has been committed or can provide a link between a crime and its victim or a crime and its perpetrator. Types of Evidence Temporary Conditional Associative Pattern Trace/Transfer -May be -Associated -Links the -Blood -Produced by changed or with specific suspect or -Impressions physical contact can be lost. conditions at victim to the -Tire treds with some surface. the crime scene. scene. -Residues that show the Modus Operandi (how it occurred)

7 Crime Scene Cont. Common Examples of Evidence -Bullets or Firearms -Glass -Fingerprints: visible or latent -Organs -Hair -Paint -Blood, Semen, Saliva -Plastic Bags -Footprints (impressions) -Plastic, Rubber, or other polymers -Documents -Powder Residue (gun) -Drugs -Soil and Minerals - Explosives -Tool Markings -Petroleum Products -Vegetative (wood, plants, etc…) - Serial Numbers -Fiber: Natural or Synthetic Common Examples of Evidence -Bullets or Firearms -Glass -Fingerprints: visible or latent -Organs -Hair -Paint -Blood, Semen, Saliva -Plastic Bags -Footprints (impressions) -Plastic, Rubber, or other polymers -Documents -Powder Residue (gun) -Drugs -Soil and Minerals - Explosives -Tool Markings -Petroleum Products -Vegetative (wood, plants, etc…) - Serial Numbers -Fiber: Natural or Synthetic

8 Crime Scene Cont.  Class Evidence -Evidence that posses characteristics that can only be associated with a group and never a single source. Ex) Blood Types  Class Evidence -Evidence that posses characteristics that can only be associated with a group and never a single source. Ex) Blood Types  Individual Evidence -Evidence that can be associated with a common source with an extreme high degree of probability. Ex) DNA  Individual Evidence -Evidence that can be associated with a common source with an extreme high degree of probability. Ex) DNA

9 Processing The Scene Secure and Isolate the Crime Scene -1st officer on the scene -Goal is to preserve and protect to the greatest extent -Only allow authorized people in -Rope and barracades Record the Scene -Limited amount of time at the scene only one shot to find everything. -Don’t want to touch anything. -Photograph the scene scale. -Sketch the scene rough and then final. -Take notes.

10 Processing The Scene Cont. Conduct a Systematic Search for Evidence -A search for physical evidence at a crime scene must be thorough and systematic: Spiral Strip or Line Grid Quadrant (Zone) s s s

11 Processing The Scene Cont. Collect and Package Physical Evidence: -The integrity of the evidence is best maintained when the item is kept in its original condition. -Do this to prevent contamination, breakage, evaporation, accidental damage, or loss. -Each piece will have its own container/bag. Maintain Chain of Custody: -The documentation on the container that shows who is and where the evidence went from the crime scene to the court house. Obtain Controls: -This is used to match evidence from the scene to an individual or known object. Submit Evidence to the Laboratory: -There are different laboratories under different jurisdictions. Depending on the investigators and type of crime depends where the evidence was sent.

12 Processing The Scene Cont. Henry Lee’s Linkage Principle: Crime Scene Victim Evidence Suspect *You need to be able to argue the case between all four “Air Tight Case” Product Rule: - The probability of independent events.

13 Crime Scene Documentation -The documentation of a crime scene consists of photographs helps document the facts and physical evidence at the crime scene. -The crime scene sketch used to plot accurate measurements made at the scene. -Taking notes Keep a log that records time of discovery of the crime. Fixed Point Method Bookshelf -Door -Window -Wall Corner -Permanent Object -Pick two fixed points -Draw a line from the point to the object.


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