csa study

Crime Scene Investigation Notes

Processing the Scene

1. Determine Team Composition

• Principle: Selecting a trained team is essential for successful scene processing.

• Policy: Investigators must assess the crime scene to determine the appropriate team composition and required resources for effective processing.

• Procedure:

  • Assess the need for additional personnel based on the complexity of the scene, the number of victims, suspects, or witnesses, and the type of evidence expected to be collected.

  • Call forensic specialists for equipment and expertise, such as crime scene analysts, forensic odontologists, or digital forensic experts, based on the specific needs of the investigation.

  • Ensure scene security to preserve evidence and prevent unauthorized entry; document all entry and exit points meticulously.

  • Select qualified personnel for various roles, including photography, sketching, and evidence collection. Ensure that team members have relevant credentials and training.

  • Document team members and their specific assignments to track responsibilities and maintain accountability throughout the investigation.

• Summary: Effective scene assessment defines the number of personnel required and their task assignments, ensuring a comprehensive approach to evidence collection and documentation.

2. Ensure Contamination Control

• Principle: Contamination control is crucial to preserve personnel safety and the integrity of evidence collected at the scene.

• Policy: All personnel involved in the investigation must adhere to strict procedures to ensure their safety and to maintain evidence integrity.

• Procedure:

  • Limit access to the scene to personnel directly involved in processing to reduce the risk of contamination and protect evidence.

  • Follow established entry and exit routes to minimize disruption to potential evidence.

  • Identify first responders clearly; their presence may necessitate the elimination of certain samples to ensure evidence quality.

  • Designate secure areas for disposing of trash and storing equipment used during the investigation.

  • Use personal protective equipment (PPE) such as gloves, masks, and protective suits to minimize contamination risks.

  • Clean and sanitize tools and equipment between collections of different evidence types to avoid cross-contamination.

  • Employ single-use equipment for collecting biological samples, like swabs or bags, to ensure that no residual traces affect subsequent evidence.

• Summary: Minimizing contamination involves adhering to safe and hygienic processing practices, ensuring the reliability of collected evidence.

3. Documentation

• Principle: A thorough scene assessment determines the required documentation forms, which can include photographs, videos, sketches, and written notes.

• Policy: Documentation of the scene must be comprehensive and accurate to support the investigation.

• Procedure:

  • Review the initial scene assessment to determine specific documentation needs based on scene complexity and evidence types present.

  • Coordinate the collection of photographs, sketches, measurements, and notes to create a complete and cohesive account of the scene.

  • Photograph the scene using a range of views, including overall shots to capture context, medium shots to focus on evidence clusters, and close-ups for detailed evidence visibility.

  • Record video as an optional supplement for visual documentation, preserving dynamic aspects of the scene.

  • Generate sketches and measure crucial details of the scene, incorporating scale for accuracy.

  • Make thorough notes covering the time, physical descriptions of evidence, conditions at the scene (e.g., weather), and any significant observations.

• Equipment Needed for Sketching: Graph paper, measuring tape, clipboard, compass, and potentially computer software for digital sketching.

4. General Considerations

• Rough sketches created at the scene are preliminary, and any alterations should be documented rather than adjusted post-scene. Accurate measurements should always be recorded diligently.

• Different types of sketches (rough, finished, aerial) should be utilized based on specific needs, ensuring that they convey critical information about the scene layout and evidence locations.

5. Prioritize Collection of Evidence

• Principle: Prioritizing evidence collection is essential to prevent the loss or contamination of evidence critical to the investigation.

• Policy: Evidence should be collected systematically, as determined by the investigator's assessment of the scene and the types of evidence present.

• Procedure:

  • Identify specific roles for team members involved in the evidence collection process to ensure all evidence is accounted for and collected properly.

  • Evaluate all possible evidence sources meticulously and prioritize them based on visibility and accessibility.

  • Begin the collection process in easily accessible areas before moving to less visible or harder to reach locations, as these may have more potential for degradation or loss of evidence.

  • Use systematic search methods based on the layout of the scene to ensure no evidence goes unnoticed.

  • Concentrate on transient evidence first (e.g., footprints or fibers) before moving on to less transient forms such as concrete or permanent markers.

• Summary: Prioritizing evidence collection helps maintain the integrity of the investigation, ensuring pivotal evidence is preserved for analysis.

6. Crime Scene Search Methods

• Principle: Comprehensive searches of the scene are fundamental to ensure that all evidence is recognized and collected.

• Policy: Various search strategies must be adapted to the specific requirements of the scene for maximum efficiency.

• Types of Searches:

  • Lane or Strip Search: Searchers walk in lanes that are parallel to each other, ensuring thorough coverage of the area.

  • Grid Search: Conduct two perpendicular lane searches to provide exhaustive coverage of the scene, reducing the likelihood of overlooked evidence.

  • Zone Search: Divide the crime scene into zones and assign searchers to be responsible for each, optimizing time and effort in larger scenes.

  • Spiral Search: Searchers spiral inward or outward from a central point, which is effective in confined spaces.

7. Collect, Preserve, Inventory, Package, Transport, and Submit Evidence

• Principle: Proper handling of evidence is crucial for the success of the investigation.

• Policy: Ensure effective management of evidence throughout the investigation lifecycle to maintain its integrity.

• Procedure:

  • Maintain security of the scene and diligently document evidence collection processes at every step.

  • Collect and label each piece of evidence carefully, ensuring a clear chain of custody is documented to prevent questions regarding evidence validity.

  • Utilize containers that are appropriate for the type of evidence collected, ensuring they prevent contamination and maintain evidence integrity.

  • Take immediate action to secure electronically recorded evidence to avoid data loss or modification.

• Summary: Effective evidence handling is essential for successful investigations and helps uphold the legal and forensic validity of findings.

8. Documentation Practices for Evidence

• Methods:

  • Collect samples of bodily fluids (e.g., blood, semen) per established packaging guidelines to ensure they are preserved correctly during transport.

  • Follow specific collection procedures for various evidence types, including gunshot residue, firearms, and trace evidence, ensuring each category is handled appropriately to avoid contamination or loss.

• Types of Evidence:

  • Gunshot Residue (GSR): Collection should be immediate using GSR kits; avoid destroying any potential evidence through improper handling.

  • Fingerprint Evidence: Use dedicated fingerprint kits; take care during collection and ensure proper packaging afterwards to preserve prints.

9. Specific Evidence Considerations

• Soil and Rock Sampling: Collect samples from described locations and be sure to document effectively regarding depth, location, and surrounding materials for proper evaluation.

• Electronic Evidence: Handle all digital and electronic devices with specialized techniques to ensure proper evidence preservation, including utilizing write-blockers when necessary.

Summary

Maintain strict adherence to protocols during crime scene processing to ensure the integrity and validity of the investigation, safeguarding both personnel and evidence throughout the entire procedure. Each step in the process plays a critical role in unraveling the facts of a case and supporting the judicial process effectively.