Comprehensive Forensics and Hair Analysis Study Guide

Group Project Logistics and Requirements

• Rationale for Group Work:

  • Forensic professionals must work closely with police officers and detectives. Understanding police operations, organizational structures, and community group interactions is essential for field and laboratory work.

• Project Topic & Selection:

  • Students may choose from a provided list of community groups or select a unique group within the community by emailing the instructor for approval.

• Formatting and Submission Guidelines:

  • Style Format: Strict APA format is required, including in-text citations throughout the slides and a reference slide at the end.
  • Submission Deadline: Presentation slides must be submitted via Canvas by October $21$.
  • Submission Review: Slides are checked for proper formatting prior to presentation day.
  • Presentation Date: Live in-class presentations take place on October $27$.

• Group Structure & Adjustments:

  • Group $1$: Annika Edwards and Collinsworth.
  • Group $2$: Izzy Hunt and Isabella (reorganized after group consolidations and after Lewis dropped from Group $3$; Group $4$ was eliminated).
  • Group $2$ is assigned to present first on October $27$.

• Presentation Structure & Execution:

  • Duration: Presentations must run between $10$ and $15$ minutes.
  • Slide Content: Must contain a clear Introduction, Body, and Conclusion.
  • Required Prompts: Presentations must detail historical police interactions with the group, current methods and goals for cultivating positive relationships with community members, and specific group recommendations for future improvements.
  • Data and Justification: Claims must be backed by evidence and statistics (e.g., demonstrating significant changes in police procedures over time).
  • Delivery Rules: Presenters must address the audience, scan the room, maintain eye contact, and avoid reading directly from note cards or turning their backs to the class.

• Grading and Assessment:

  • The project is worth $75$ points.
  • A single grade is generally awarded per group. If a group member fails to contribute, other members must email the instructor detailing the lack of participation so individual grade adjustments can be made.
  • Attendance on presentation day is strictly mandatory; non-attendance results in no grade.

Forensic Investigation Roles and Crime Scene Protocols

• Division of Labor Between Detectives and Forensics:

  • Both roles address the core investigative questions: Who, What, When, Where, How, and Why.
  • Detectives: Focus on field investigations, obtaining search warrants, interviewing witnesses, canvassing neighborhoods, and investigating victim backgrounds (financial records, social media, online comments, threats, hate group affiliations, and personal associations).
  • Forensic Scientists: Focus on applying scientific methodology to evaluate physical evidence in a laboratory setting to scientifically link a suspect to a crime scene and ensure evidence withstands judicial scrutiny.

• Jurisdiction and Scene Ownership:

  • Law enforcement owns and secures the physical crime scene using search warrants.
  • The body is processed by the Medical Examiner / Coroner in a laboratory or morgue setting after removal from the scene to evaluate toxicology and determine cause/probable cause of death.

• Jurisdictional Escalations & FBI Involvement:

  • If local jurisdictions lack funding or specialized testing capabilities, evidence is sent to the FBI Crime Lab.
  • Crimes crossing state lines (interstate crimes) or complex serial crimes (serial murders, abductions, kidnappings) involve federal agencies and behavioral profilers to analyze criminal patterns, pathology, psychology, and criminology.

• Documentation and Chain of Custody:

  • Every piece of physical or photographic evidence must be recorded on a crime scene log.
  • Photographic logs must account for the camera type, digital storage/film details, frame numbers, subject description, and the identity of the photographer.
  • Maintaining an unbroken chain of custody is legally required to prevent defense attorneys from invalidating evidence in court.

• Digital Reconstructions:

  • Digital forensic programs utilize physical data (such as blood spatter patterns) to run virtual simulations, determining bullet trajectories, angles, and shooter characteristics (such as height).

Biological Structure and Life Cycle of Hair

• Biological Functions of Hair:

  • Regulates body temperature.
  • Decreases friction.
  • Protects skin against sunlight and sunburn.

• Follicle Statistics:

  • Humans are born with approximately $5,000,000$ hair follicles.
  • Only $2\%$ of total body hair follicles are located on the head.
  • Total active hair follicles decrease with age.

• Anatomy of Hair:

  • Hair Shaft: The non-growing portion of hair produced inside the follicle; contains keratin protein, trace elements, and mitochondrial DNA.
  • Hair Root: The base portion of the hair strand beneath the surface.
  • Hair Follicle: A club-like structure in the skin containing papillae, capillaries, blood vessels, and sebaceous glands.
  • Sebaceous Glands: Specialized oil-secreting glands attached to the follicle (distinct from sweat glands).

• The Three Stages of the Hair Life Cycle:

  1. Anagen Stage: The active growth period, lasting approximately $1,000$ days.
  2. Catagen Stage: Growth stops, and blood supply to the hair follicle is reduced.
  3. Telogen Stage: The hair follicle goes dormant; this stage serves as a primary source for trace evidence.

Evidence Collection Methodologies for Hair

• Investigative Contexts:

  • Detailed hair collection is critical in serious criminal cases, including homicides, kidnapping, and sexual assault investigations.

• Firmly Attached Hair (e.g., attached to clothing, weapons, shoes):

  • Diagram the precise location of the hair on the item.
  • Photograph the hair in place.
  • Package the entire item of clothing or object containing the hair.
  • Drying Requirement: Damp or wet items containing evidence must be dried prior to packaging to prevent mold growth and total decomposition.

• Unattached / Loose Hair:

  • Photograph the hair in situ (in its original position as found).
  • Use clean, sterilized forceps to pick up the hair strand.
  • Package the hair strand into a small sterile box or sealed glass vial.

• Physical Removal Techniques:

  • Methods for collecting hair from surfaces include plucking, shaking, surface scraping, pubic hair combing, and lifting via clear plastic tape.
  • Forensic vacuums equipped with single-use, sterile collection tools are used to collect loose trace evidence (household vacuum cleaners from a scene may also be seized and examined for evidentiary contents).

Microscopic, Chemical, and DNA Analysis of Hair Evidence

• Macroscopic Analysis:

  • Visual inspection with the naked eye to assess physical characteristics: length, color, curliness, and texture.
  • Yields broad class evidence.

• Microscopic Analysis:

  • Differentiates between human and non-human hair.
  • Examines structural layers:
    • Medulla: The innermost layer of the hair shaft.
    • Cortex: The middle layer containing pigment granules.
    • Scales: The outermost pattern layer.
  • Trace Contaminants Analysis:
    • Pollen: Identifies specific geographical locations, plant species, or seasonal environments.
    • Hair Products: Identifies specific gels, sprays, or chemical treatments used by a suspect or victim.
    • Dandruff: Provides dead skin cell material.
    • Sawdust / Wood Particles: Indicates physical presence in specific environments such as lumber mills, forestry operations, or furniture workshops.

• Chemical Analysis:

  • Chemicals absorbed through skin or ingested enter the bloodstream and become permanently incorporated into the hair structure.
  • Hair resists rapid decomposition, providing a long-term timeline of exposure.
  • Diagnostic Capabilities:
    • Detects nutritional deficiencies, pointing to crimes such as prolonged captivity, kidnapping, or abuse (child, elder, or animal abuse).
    • Detects toxic substances and heavy metals, establishing timelines for acute or chronic poisoning (e.g., rat poison, ricin).
  • Laboratory Methods: Hair is dissolved in organic solvents and analyzed using Gas Chromatography (GC) or Liquid Chromatography to quantify drugs, heavy metals, and toxins. Isotope Ratio Analysis provides precise data on an individual's geographical history, age, and diet.

• DNA Profiling from Hair:

  • Nuclear DNA:
    • Obtained strictly from the hair follicle or root ball.
    • Extracted, amplified, and processed to create an automated profile.
    • Provides individual evidence linking a specific person to a scene.
  • Mitochondrial DNA (mtDNA):
    • Located in circular chromosomes within cells of the hair shaft (present when no root or follicle is attached).
    • Inherited exclusively through the maternal line.
    • Determines maternal family relationships and ancestral lineages.
    • Categorized as class evidence if specific maternal lineage cannot be uniquely isolated.

Legal Concepts: Class vs. Individual and Direct vs. Circumstantial Evidence

• Class Evidence vs. Individual Evidence:

  • Class Evidence: Group-level categorization (e.g., hair color, general texture, hair shaft lacking a root ball, mtDNA).
  • Individual Evidence: Uniquely identifies a single source with high probability (e.g., nuclear DNA extracted from a root ball or follicle).

• Direct Evidence vs. Circumstantial Evidence:

  • Circumstantial Evidence: Physical hair presence indicates that physical contact occurred, but cannot independently prove guilt or establish the exact moment the hair was deposited (due to potential secondary transfer, such as moving a body).
  • Direct Evidence: Highly specific nuclear DNA matches from intact root follicles directly link a suspect's biological material to a victim or scene, providing direct probative evidence in court.