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Introduction to Forensic Science

Introduction to Forensic Science. Forensic Science. Involves the application of scientific theory, process, and techniques in legal matters. Primary role of a forensic scientist is to analyze evidence gathered at a crime scene. Science Disciplines Needed. Biology Physics Geology

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Introduction to Forensic Science

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  1. Introduction to Forensic Science

  2. Forensic Science • Involves the application of scientific theory, process, and techniques in legal matters. • Primary role of a forensic scientist is to analyze evidencegathered at a crime scene.

  3. Science Disciplines Needed • Biology • Physics • Geology • Anthropology • Psychiatry • Photography • Toxicology • Ballistics • Odontology (in forensics: examination of bite marks and dental identification of corpses) • Engineering • Chemistry • Computer technology • Pathology (investigation of a sudden, unexplained death) • Environmental science • Entomology (study of insects, particularly decomposers in forensics) • Palynology (study of pollen and spores) • Polygraphy(use of lie detectors)

  4. Locard’s Exchange Principle • Edmond Locardwas a pioneer in the field of forensic science. • He became known as “The Sherlock Holmes of France.” • In 1910, when he opened his forensic lab, he stated that whenever an individual comes in contact with a crime scene or victim, there will be an exchange of materials between them.

  5. Two Types of Evidence • Testimonial evidence:prima facie evidence or direct evidence, a statement made by a competent witness under oath. • Physical evidence: real evidence; any object or material relevant to a crime.

  6. Example of Physical Evidence • Hair, fibers, soil, glass, body fluids, fingerprints, pollen, bones, toxic substances, documents, firearms, ammunition, gunshot residues and impressions (bite marks, shoeprints, etc.)

  7. Types of Physical Evidence • Individual: linked to a single source • Examples: fingerprints and footprints • Class: Material that can be linked to only a group of items with similar properties • Examples: hair and blood type

  8. Two Forms of All Evidence • Both testimonial or physical evidence can be either direct or circumstantial evidence. • Direct evidence: links the suspect to the crime • Examples: blood alcohol content or possession of an illegal substance • Circumstantial evidence: points to a possibleconnection between the evidence and the suspect

  9. Forensic Evidence Databases • The National Integrated Ballistics Information Network (NIBIN) allows the comparison of markings made by a firearm on bullets and cartridge casings. • The International Forensic Automotive Paint Data Query (PDQ) contains chemical and color information pertaining to original automotive paints. • SICAR (shoeprint image capture and retrieval) is a shoeprint database. • TheIntegrated Automated Fingerprint Identification System (IAFIS), a national fingerprint and criminal history system maintained by the FBI. • The Combined DNA Index System (CODIS) enables federal, state, and local crime laboratories to electronically exchange and compare DNA profiles.

  10. The Crime Scene • Forensics begins at the scene of the crime. • Careful, objective, and scientific treatment of all evidence must occur. • If not, vital evidence may be overlooked, damaged, or contaminated; making it useless in a court of law.

  11. Primary CSI Procedures • Interview • Examine • Photograph • Sketch • Process • Tag all evidence with a number. • Photograph it. • Package it. • Label it.

  12. Notes • Police notes begin with your assignment to the case and continue to the end of the investigation. • Supplement all photos, sketches, and scale drawings. • Print with a smudge-proof blue or black ink. • Number and identify each page with your name, title, case number, and date. • Record the time an action was taken, information received, or event was observed. • Do not edit or erase. Line out the entry, initial, and rewrite.

  13. Forensic Photography • No objects are removed until they have been photographed from all necessary angles. • Three ranges of picture documentation: • Overview • Intermediate • Close-up (close and perpendicular to the object.)

  14. Photo Log Information • Assign each photo a number. • Describe photo contents. • Cite the time the photo was taken, the type of photo, and the distance to the focal point. • List the type of camera used and the height at which it was held.

  15. Additional Photo Log • List the position of the camera or the angle of the camera shot. • List what lens was used; whether a flash was used; and whether digital or the type of film. • If film, note when new film is loaded. • Note all data on a photo sketch, as well as in your notes.

  16. Crime Scene Sketches • Aerial view of the entire crime scene • Rough sketch vs. finished drawing

  17. Elements of Sketching • Measurements • Compass directions • Essential items • Scale or proportion • Legend • Title (case-file # and offense) • Projection • Surveying methods • Rectangular (hypotenuse) or polar coordinates (length and angle.)

  18. Projection Drawing • Looks like a box with all four sides flattened.

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