4FO511_2024-2025_Week 6_part 7-9_StudV

Structure of Crime Scene Investigation

• Overview: The crime scene investigation process is divided into several key components that guide the exploration, documentation, and safeguarding of the area where a crime has occurred.

  1. Crime scene and field of investigation

  2. Scene of investigation and traces

  3. Intervention at the scene of investigation

  4. Documentation and recording of the scene

  5. Protection and control of the scene of investigation

  6. The decision to intervene

  7. Examination of the scene

  8. Use of traces in the investigation

  9. Conclusion

Examination of the Scene

• Focus: The examination is critical in the investigation, emphasizing thoroughness in searching, detecting, recording, collecting, sampling, and packaging relevant traces or items.

Protective Measures for Investigators

• Importance of Protection: Ensuring the safety of both evidence and personnel is paramount in any investigation.

  • Precautions include:

    • Wearing protective suits (and overshoes)

    • Using gloves, masks, and possibly goggles

    • Depending on scenario, a tent may be utilized

Methodological Approach to Investigation

• Systematic Approach: A structured and methodical investigation is essential, characterized by:

  • Rigorous and cognitive strategies

  • Documentation of all procedures and findings

  • Coordination among team members

  • Prior analysis and consensus on the action plan before proceeding.

• Importance of reflection, attention, and precision in exploiting the crime scene optimally, following a systematic search that moves from general observations to specific details.

Time Considerations at the Scene

• Variable Duration: The time spent at a crime scene can vary greatly:

  • For burglaries, UK studies show an average of 16-30 minutes in 2007, extending to 30-60 minutes in 2022.

  • In Switzerland, investigators reportedly spend a total of 90 minutes (including travel).

  • In Australia, total time averages around 4.5 hours, encompassing 4 hours of travel and 30 minutes on-site.

Detection and Search Methodologies

• Hypothetico-Deductive Reasoning: Implementing a structured approach in evidence detection and analysis, including:

  • Observation and situational analysis

  • Physical analysis of the scene and transfer conditions

  • Testing hypotheses based on expected outcomes.

• Example Methodologies:

  • Using oblique lighting for scanning floors and careful observation to detect shoe imprints or other traces.

  • Understanding potential for false positives or negatives in assessments.

Equipment for Evidence Collection

• Essential Materials: Different materials and equipment must be used for optimal search and collection:

  • Personal Protection: gloves, masks, suits, overshoes, goggles

  • Documentation Tools: cameras, markers, imaging devices

  • Search Tools: lighting sources, magnification equipment

  • Techniques for developing latent traces such as powders for fingerprints, shoe marks, and blood traces.

Techniques for Latent Trace Detection

• Specific Materials for Detection:

  • Various powders (like black, white or luminescent) for collecting fingerprints on surfaces.

  • Various other techniques including Small Particle Reagent (SPR) for wet surfaces, iodine fuming, and electrostatic lifts for recovering shoes marks.

  • Using Gelatine Lifts for capturing imprints from surfaces, enhancing the collected images for analysis.

Biological Sampling and Kits

• Swab Collection Kits:

  • For recovering biological evidence such as blood, tissues, or other cellular materials.

  • Essential for high-quality evidence collection in forensic investigations.

Documentation and Evidence Handling

• Critical Aspects: The documentation of the chain of custody is crucial due to its role in legal processes. This involves:

  • Clear records of evidence collection with special attention to the context, allowing evidence to be admissible in court.

  • Handling specifics, including sealing and labeling protocols to prevent contamination or alteration.

Conclusion of Crime Scene Investigation

• Learning Objectives: Understanding the diverse ranges of knowledge required in examining and documenting crime scenes to inform investigative procedures and outcomes. This includes:

  • Technical know-how, the genesis of evidence types, and their processes of transfer and preservation.

  • Recognition of different crime scene demands and situational reasoning for decision-making processes.

  • Emphasizing the ongoing necessity for documentation and adherence to protocols to maintain the integrity of evidence.