Review Exam 1 - Forensic Science (Chapters 1-6)

Chapter 1

• Definition of forensic science
  • Forensic science is the application of scientific methods and principles to matters of law, especially evidence arising from criminal investigations.
  • It is presented as an applied discipline that supports legal processes rather than a standalone branch of science itself.
• Why forensic science is not a branch of science
  • It applies established scientific techniques to legal questions, rather than constituting a separate scientific theory or domain.
  • It integrates methods from multiple natural and physical sciences to answer questions of fact in court.
• History and development of forensic science (who did what)
  • The chapter emphasizes knowing the historical development and key contributors to forensic science.
  • Context includes early techniques and milestones that shaped how evidence is collected, analyzed, and interpreted in legal settings.
• Locard’s Exchange Principle and its importance
  • Principle: Every contact between two objects results in an exchange of material, meaning that both the crime scene and the offender become trace carriers for each other.
  • Importance: Provides a foundational basis for linking suspects to scenes and victims through transferred evidence; underpins the collection and analysis of trace materials.
• Location of the oldest crime lab
  • The oldest crime laboratory location is highlighted (historical reference point relevant to the evolution of organized forensic labs).
• Significance of the FBI to forensic science
  • The FBI has played a major role in standardizing practices, funding, research, and the development of shared databases and protocols used nationwide.
• Types of crime labs
  • Crime labs can be local, state, and federal; they vary in scope and specialization.
  • Some labs focus on drug analysis, DNA, firearms, trace evidence, etc., depending on jurisdiction and need.
• What determines the size of a crime lab
  • Population served, caseload, and complexity of cases.
  • Budget, available facilities, and staff expertise.
  • Scope of services (e.g., presence of multiple units such as biology, chemistry, firearms).
• Units in a crime lab and the evidence each analyzes
  • Biology/DNA Unit: analyzes biological evidence (blood, semen, saliva, DNA).
  • firearms/Toolmark Unit: analyzes firearm-related evidence and toolmark impressions.
  • Chemistry/Drug Unit: analyzes controlled substances and chemical evidence.
  • Toxicology Unit: analyzes poisons and toxic substances.
  • Physical Evidence/Trace Evidence Unit: handles fibers, hairs, glass, paints, soils, and miscellaneous trace evidence.
  • Document Examination Unit: analyzes handwriting and documentary evidence.
  • Latent Print Unit: developing and comparing latent fingerprints.
  • Photography/Imaging Unit: documents crime scenes and evidence visually.
  • Administrative/Support Units: chain of custody, evidence handling, and quality control.

Chapter 2

• Responsibilities of the first officer at the crime scene
  • Secure the scene to prevent contamination or loss of evidence.
  • Provide care for any victims and render aid if needed.
  • Establish a perimeter and control access to the area.
  • Initiate preliminary documentation and coordinate with investigators.
• Responsibilities of the lead investigator
  • Oversee scene management, evidence collection strategy, and overall investigation direction.
  • Ensure proper documentation, sketched layouts, and adherence to procedures.
• Documentation of a crime scene and why each method is used
  • Notes: written observations and time-stamped details.
  • Photography: visual record of evidence and scene condition.
  • Videography: dynamic, continuous documentation of the scene.
  • Sketches/ diagrams: spatial relationships and measurements for reconstruction.
• Clothing collected from a suspect and why
  • To preserve potential trace evidence (fibers, fibers in fabric, skin cells, residues) and to document the condition of the suspect at the time of arrest.
• Evidence collected from the victim and why
  • To document injuries, locate trace materials on or around the victim, and identify possible sources of biological, biochemical, or trace evidence.
• Handling of trace evidence
  • Avoid contamination, use proper packaging, and maintain chain of custody.
• Tools and packaging materials carried by evidence collectors
  • Gloves, appropriate bags/envelopes, forceps, swabs, evidence markers, labels, and tamper-evident seals.
• Chain of custody and its significance
  • Paper trail documenting every person who handled the evidence, with dates, times, and purposes.
  • Essential for admissibility in court; ensures evidence integrity.
• Information used to mark physical evidence
  • Evidence identifiers (case number, item number), date/time, collector initials, and a brief description.
• Difference between standard and reference samples
  • Standard samples: known reference materials used to calibrate tests and procedures.
  • Reference samples: materials from a suspect or unknown source used for comparison.

Chapter 3

• Common types of physical evidence
  • Fibers, hairs, glass, paints, soils, drugs, weapons, toolmarks, fingerprints, handwriting, documents, digital evidence, etc.
• Individual vs class characteristics
  • Individual characteristics: unique features that can identify a specific source (e.g., a unique toolmark, a unique fingerprint ridge detail).
  • Class characteristics: shared features that can associate evidence with a group (e.g., type of glass, common fiber type).
• Significance of individualized vs class evidence
  • Individual evidence provides strong, source-specific links to a single item or person.
  • Class evidence narrows the pool of possible sources and supports broader associations.
• Types of physical evidence (repeat emphasis)
  • See above for examples; emphasizes identification and classification.
• Why physical evidence must be identified
  • Proper identification guides the appropriate analysis, packaging, and interpretation.
• Which physical evidence can be individualized and why
  • Evidence with unique, source-specific characteristics (e.g., a unique toolmark, a unique fingerprint detail) can be individualized due to distinct patterns or marks.
• Functions of the forensic scientist
  • Collect, analyze, interpret, and present evidence.
  • Provide expert testimony when qualified.
• Qualifications to be an expert witness
  • Demonstrated knowledge, training, experience, and evidence-based methodology; ability to explain findings clearly to a lay audience and the court.

Chapter 6

• Common ridge characteristics of a fingerprint
  • Minutiae such as bifurcations, ridge endings, deltas, sidepoints, and cores.
• The three major fingerprint patterns
  • Loops, whorls, arches.
• Distinguish visible, plastic, and latent fingerprints
  • Visible: made by touching surfaces with the finger still coated in ink or other substances.
  • Plastic: an impression left in soft surfaces (e.g., wax, clay).
  • Latent: invisible to the naked eye, requiring development techniques.
• Concept of AFIS (Automated Fingerprint Identification System)
  • A computerized system used to store, search, compare, and retrieve fingerprint data.
• Techniques for developing latent fingerprints on porous and nonporous objects
  • Porous surfaces (e.g., paper): chemical methods such as ninhydrin, physical developer; may involve iodine fuming as a preliminary step.
  • Nonporous surfaces (e.g., glass, metal, plastic): dusting powders, iodine fuming, cyanoacrylate (superglue) fuming, fluorescence techniques.
• Proper procedures for preserving a developed latent fingerprint
  • Photograph and lift or collect the print using appropriate materials; avoid contamination; document the method and location.
• Why a fingerprint can be individualized
  • Based on unique ridge patterns and minutiae points which are highly unlikely to be identical between individuals.
• How to obtain a Henry number for an individual
  • Henry classification system for fingerprint patterns used to categorize prints for filing and searching.
• Why a Henry number is not individualized data
  • The Henry system provides a classification that helps organize prints; it does not uniquely identify an individual by itself.
• Methods used to develop latent fingerprints
  • Chemical (ninhydrin, physical developer), physical (powders), and instrumental methods (alternate light sources, fluorescence).
• Other prints useful in linking an individual to a crime scene
  • Palm prints, footprints, bite marks, toolmarks, handwriting comparisons, and other biometrics beyond fingerprints.
• What can be found in the AFIS database
  • Matches to known prints in the system, potential candidate identifications, and associated metadata (e.g., source, date).
• Difference between Live Scans and Dead Scans
  • Live Scans: digital capture of fingerprints from a living person using a live-scan device.
  • Dead Scans: latent or lifted prints from surfaces, analyzed and stored in databases.