Comprehensive Study Notes on Crime Scene Investigation

1. Learning Objectives

By the end of this lesson, students should be able to:

  • Provide comprehensive definitions for key terms relevant to crime scene investigation.

  • Discuss the responsibilities of the first police officer arriving at a crime scene.

  • Explain the steps for thoroughly recording a crime scene.

  • Prepare proper crime scene sketches based on methods described in the textbook and by instructors.

  • Describe procedures for conducting a systematic search of crime scenes for physical evidence.

  • Describe techniques for packaging common types of physical evidence.

  • Define and demonstrate an understanding of the significance of the “chain of custody.”

  • Relate steps necessary to maintain appropriate health and safety standards at the crime scene.

Prescribed Reading

Saferstein, R. (2020). Criminalistics: An Introduction to Forensic Science (13th ed.). Pearson. ISBN: 9780135218310, Chapter 2.

2. Crime Scene Investigation

Crime scene investigations are crucial when determining the truth concerning a crime. Each situation can vary significantly, examples include:

  • A body washing ashore on a deserted beach.

  • A fire in an apartment complex that was used as a narcotics laboratory.

  • A fatal car crash resulting in one or more deaths.
    The primary aim of criminal investigation is the diligent search for truth whereby systematic examination of crime scenes unveils forensic evidence. Evidence at crime scenes comes in two forms:

  • Objective clues: These are factual, physical evidence and include indirect or circumstantial evidence.

  • Subjective clues: This type comes from individuals such as victims, witnesses, and suspects who provide evidence through testimony.

Types of Crimes

Some examples of crimes include:

  • Arson: The intentional destruction of property by fire.

  • Burglary: Unauthorized entry with the intent of committing theft.

  • Fraud/forgery: The act of deceit through creating or altering documents.

  • Murder: The unlawful premeditated killing of another person.

  • Manslaughter: The unintentional killing of another person.

  • Kidnapping: Abduction of an individual against their will.

3. Objectives of a Crime Scene Investigation

A successful crime scene investigation aims for several objectives:

  1. Identification of the Crime: Determine the type and context of the crime committed, including confirming unlawful acts under juridical standards.

  2. Gathering of Evidence: Collect all information, both oral and physical, that will enable the court to resolve factual disputes.

  3. Individualisation of the Crime: This involves categorization versus individualization, typically comparing evidence against known individuals for identification (e.g., fingerprints).

  4. Arrest of the Criminal: Ensure that suspects are apprehended to facilitate their appearance in court.

  5. Recovery of Stolen Property: Seize property that can serve as evidence and ultimately be returned to the owner after legal proceedings.

  6. Involvement in the Prosecution Process: Criminal investigators may support prosecutors by ensuring evidence is presented correctly in court.

4. Roles and Responsibilities at Crime Scenes

Understanding the roles of individuals at a crime scene enhances the investigation's effectiveness. The primary personnel involved are noted below:

4.1. First Member

  • The first officer on the scene evaluates the condition of the victim(s) and prioritizes life preservation if needed. Responsibilities include:

    • Assisting the victim.

    • Searching for and apprehending suspects.

    • Detaining witnesses.

    • Protecting and securing the scene using SAPS identifying tape.

    • Reporting movements made within the scene to subsequent investigators.

4.2. Crime Scene Manager

  • Takes charge of the crime scene upon arrival of the forensic department. Responsibilities include:

    • Delegating tasks to crime scene technicians and investigating officers.

    • Conducting a "first walk" through to identify evidence collection routes.

4.3. Photographer

  • Responsible for documenting the scene through photography and often video. It’s critical that evidence is captured before any alterations.

4.4. Crime Scene Technician

  • Analyzes small details within the scene, collecting evidence such as DNA under ultraviolet light. Technicians must maintain meticulous records and manage evidence for transport to laboratories.

4.5. Activity

Students are required to watch videos and observe personnel's crime scene approaches and assigned tasks.

5. Phases of Crime Scene Investigation

The phases of crime scene investigation are grouped into three critical categories:

1. Pre-investigative Phase

  • Initial response includes taking control, securing the scene, and handing over to a criminal investigator.

2. Investigative Phase

  • Conducted by investigators, emphasizing thorough evidence search, documentation, and preservation of integrity.

3. Post-investigative Phase

  • Focuses on concluding the initial investigation while gathering and integrating information for analysis.

Key Principles

  • Causality: Establishing interaction between evidence and the suspect.

  • Physical Integrity: Ensuring collected evidence remains undamaged and untainted.

  • Continuity of Possession: Maintaining secure tracking of evidence from the scene to analysis to preserve quality and legal validity.

5.1. Secure and Isolate Scene

Nine critical steps include:

  1. Taking control and requesting backup as necessary.

  2. Securing the scene to ensure no additional evidence is lost.

  3. Removing unauthorized individuals away from the scene.

  4. Recording the identities of all present.

  5. Ensuring the separation of suspects from witnesses.

  6. Preventing discussion about the incident among those present.

  7. Observing bystanders for other crucial information.

  8. Documenting timelines of scene interactions.

  9. Maintaining contamination control.

5.2. Systematic Evidence Search

Investigators must carry out systematic searches to ensure thorough evidence gathering, documenting in a detailed manner. Methods include:

  • Strip Method: Walking a set path systematically.

  • Wheel Method: Multiple teams searching from a central hub.

  • Spiral Method: Expansively widening circle searches.

  • Zone Method: Dividing areas into squares for detailed investigation.

  • Grid Method: Overlapping searches for comprehensive coverage.

  • Link Method: Connecting evidence found throughout searches.

5.3. Recording Scene

Key methods for recording evidence include:

  • Note-taking: Records details to aid in trial support.

  • Photography: Must document the scene without any alteration post-arrival.

  • Sketching: Visual representation aiding the investigation and trial process, including marking positions and dimensions of evidence.

5.4. Collecting and Packaging Physical Evidence

Conducted with precision starting from fragile evidence first, ensuring each type of evidence is correctly preserved.

General Considerations:

  • Items must be packed securely, often in primary and secondary containers.

  • Items like biological evidence must be treated with particular care to ensure they do not decompose or contaminate others.

5.5. Activity

Reflect on roles and responsibilities at crime scenes to identify involvement stages and tasks.

6. Crime Scene Considerations

Critical considerations for crime scene investigators include:

6.1. Recreating the Crime Scene

Utilizing existing knowledge to draw conclusions through reasoning methods including:

  • Inductive Reasoning: Observing specific examples to form general conclusions.

  • Deductive Reasoning: Starting from a general premise to derive specific conclusions.

  • Abductive Reasoning: Making educated guesses based on incomplete evidence.

6.2. Chain of Custody

Defined as a documented list of all individuals who handle evidence, crucial for maintaining integrity and validity in legal settings. Procedures include proper recording and minimizing contact to maintain the evidence chain.

6.3. Standard/Reference Samples

Using known samples for comparison with evidence collected, must ensure proper documentation of all forms of evidence to avoid contamination.

6.4. Legal and Safety Considerations

Legal requirements must guide the submission of evidence to laboratories, including proper documentation (e.g., forensic examination request forms) and maintenance of a safe environment for investigators to avoid exposure to hazards. Investigators must be aware of potential biohazards and employ safety measures to minimize risks.

When processing evidence, care must be taken to ensure all items are handled with appropriate packaging and sealed to maintain evidence integrity.

This ensures a thorough understanding of the processes, methods, and legal aspects of crime scene investigation.

1. Learning Objectives

By the end of this lesson, students should be able to:

  • Provide definitions for key terms in crime scene investigation.

  • Discuss the first police officer's responsibilities at a crime scene.

  • Explain steps for recording a crime scene.

  • Prepare crime scene sketches based on textbook methods.

  • Describe how to conduct systematic searches for evidence.

  • Explain techniques for packaging physical evidence.

  • Understand the significance of the "chain of custody."

  • Relate necessary steps to maintain health and safety at crime scenes.

Prescribed Reading

Saferstein, R. (2020). Criminalistics: An Introduction to Forensic Science (13th ed.). Pearson. ISBN: 9780135218310, Chapter 2.

2. Crime Scene Investigation

Crime scene investigations are essential for uncovering the truth about crimes, with varying circumstances such as:

  • A body found on a beach.

  • A fire in a narcotics lab.

  • A fatal car accident.
    The goal is to systematically examine crime scenes to reveal forensic evidence, which can be:

  • Objective clues: Factual, physical evidence.

  • Subjective clues: Evidence based on testimonies from victims, witnesses, and suspects.

Types of Crimes

Examples include:

  • Arson: Intentional property destruction by fire.

  • Burglary: Unauthorized entry to commit theft.

  • Fraud/forgery: Deceit through document alteration.

  • Murder: Unlawful premeditated killing.

  • Manslaughter: Unintentional killing.

  • Kidnapping: Abduction against someone's will.

3. Objectives of a Crime Scene Investigation

Key objectives include:

  1. Identify the Crime: Determine the type and context of the crime.

  2. Gather Evidence: Collect all information to resolve disputes.

  3. Individualise the Crime: Compare evidence to known individuals (e.g., fingerprints).

  4. Arrest the Criminal: Apprehend suspects for court appearances.

  5. Recover Stolen Property: Retrieve items that serve as evidence to return to owners.

  6. Prosecutorial Involvement: Support prosecutors in court with evidence.

4. Roles and Responsibilities at Crime Scenes

Key personnel include:

4.1. First Officer

  • Evaluates victims and prioritizes preserving life. Responsibilities:

    • Assist the victim.

    • Search for and apprehend suspects.

    • Detain witnesses.

    • Protect the scene with SAPS tape.

    • Report movements to investigators.

4.2. Crime Scene Manager

  • Manages the scene upon forensic team arrival:

    • Delegates tasks.

    • Conducts initial evidence walkthrough.

4.3. Photographer

  • Documents the scene using photographs and videos, crucial before any changes.

4.4. Crime Scene Technician

  • Examines details, collects evidence (e.g., DNA), and maintains records for lab transport.

4.5. Activity

Students watch videos to observe roles and tasks at crime scenes.

5. Phases of Crime Scene Investigation

Divided into three phases:

1. Pre-investigative Phase

  • Control the scene, secure it, and hand over to investigators.

2. Investigative Phase

  • Conduct thorough evidence search, documentation, and integrity preservation.

3. Post-investigative Phase

  • Concludes initial investigations and gathers information for analysis.

Key Principles

  • Causality: Evidence interaction with the suspect.

  • Physical Integrity: Evidence must stay undamaged.

  • Continuity of Possession: Secure tracking of evidence to preserve quality.

5.1. Secure and Isolate Scene

Nine steps to secure a scene:

  1. Take control and request backup.

  2. Secure the scene to prevent evidence loss.

  3. Remove unauthorized individuals.

  4. Record identities of all present.

  5. Separate suspects from witnesses.

  6. Prevent discussion about the incident.

  7. Observe bystanders for crucial information.

  8. Document timelines of interactions.

  9. Control contamination.

5.2. Systematic Evidence Search

Methods for thorough search:

  • Strip Method: Set path along the scene.

  • Wheel Method: Teams search from a hub.

  • Spiral Method: Expanding circle searches.

  • Zone Method: Divide areas for detail.

  • Grid Method: Overlapping searches.

  • Link Method: Connecting evidence during searches.

5.3. Recording Scene

Methods include:

  • Note-taking: Records key details.

  • Photography: Documents the scene.

  • Sketching: Visual aid for investigations and trials.

5.4. Collecting and Packaging Physical Evidence

Begin with fragile evidence, securely packed.

  • Use primary and secondary containers.

  • Handle biological evidence carefully.

5.5. Activity

Reflect on roles and tasks in investigations.

6. Crime Scene Considerations
6.1. Recreating the Crime Scene

Utilizing reasoning methods:

  • Inductive Reasoning: General conclusions from specific examples.

  • Deductive Reasoning: Specific conclusions from general premises.

  • Abductive Reasoning: Educated guesses from incomplete evidence.

6.2. Chain of Custody

A documented list of all individuals handling evidence, critical for legal integrity.

6.3. Standard/Reference Samples

Using known samples for comparison while avoiding contamination.

6.4. Legal and Safety Considerations

Must comply with legal requirements for evidence submission, ensuring safety from biohazards and maintaining evidence integrity.
This enhances the understanding of processes, methods, and legal aspects in crime scene investigation.