05. Forensic Chemistry
Forensic Event
Coordinator: Prof. David Fisher and Dr. Sai Casado Zapico
Important: All documents and files, for this Event 5 only, for your experiment must be submitted by May 19th, 2025!
Background
The increasing use of plastics in everyday life also means that plastic items are commonly encountered at crime scenes. Consequently, the ability to recover latent fingerprints from plastic surfaces is crucial in forensic investigations. Plastics can present a challenge to fingermark recovery due to the variety of physical and chemical properties. These materials may also start to decompose or break down rapidly under specific conditions like high humidity and sunlight, making the process of fingerprint development more complex.
Understanding the chemistry of different plastics and how they interact with fingerprint development techniques is essential. Traditional methods may not be as effective on newer, more environmentally sustainable materials. Therefore, research and adaptation are necessary for reliable forensic analysis.
This lab event is designed to promote critical thinking, problem-solving, and collaboration among students while addressing the relevant theme of chemistry in plastics and their environmental impact. By researching and applying forensic techniques, students will gain a deeper understanding of the chemical principles involved in latent fingerprint development and the challenges posed by new plastic materials.
Objective
This event challenges teams to:
• Research and select an appropriate method for latent fingerprint development on plastic surfaces.
• Prepare a Standard Operating Procedure (SOP) for their chosen method.
• Develop latent fingerprints on a plastic item of evidence.
• Lift and compare the developed latent prints to known 10-print cards to identify potential suspects.
Safety
• Personal Protective Equipment (PPE): Each team member must wear appropriate PPE, including gloves, safety glasses, and lab coats, throughout the experiment.
• Chemical Handling: All chemicals must be handled in a fume hood to minimize exposure to hazardous vapors. Refer to the Material Safety Data Sheets (MSDS) for all chemicals used.
• Cyanoacrylate Fuming: This process should be performed in a dedicated fuming chamber to avoid inhalation of fumes.
• Solvent Use: Use flammable solvents in well-ventilated areas and keep away from open flames or heat sources.
• Waste Disposal: Dispose of all chemical waste according to established environmental safety protocols. Ensure proper segregation of waste.
Prior to the Event
1. Team Selection: Teams should consist of 3-4 high school students.
2. Method Research: Each team will select and research a procedure for latent fingerprint development on plastic items. This may include, but is not limited to:
◦ Cyanoacrylate fuming
◦ Fingerprint powders (black, magnetic, fluorescent)
◦ Fluorescent dye staining
3. SOP Preparation: Teams will prepare a detailed SOP for their chosen method, including:
◦ List of materials and equipment
◦ Step-by-step procedure
◦ Safety precautions
◦ Waste disposal methods
4. Submission: The SOP must be submitted electronically by May 19th for review by the judges.
Day of Event
1. Evidence Presentation: Each team will receive a plastic item of evidence (e.g., a plastic bottle, bag, or container).
2. Latent Print Development: Teams will use their pre-selected method and SOP to develop latent fingerprints on the item of evidence.
3. Lifting: Developed fingerprints must be carefully lifted using appropriate lifting tape or other materials.
4. Comparison: Each team will be provided with three known 10-print cards from three suspects.
5. Analysis: Teams will compare the lifted latent prints with the known prints to identify any potential matches.
6. Presentation: Each team will prepare a brief PowerPoint presentation (2-3 slides) summarizing their method, results, and conclusions.
Judging Criteria (100 Points Total)
- SOP (20 points):
◦ Clarity and completeness of the procedure
◦ Appropriateness of the chosen method for plastic surfaces
◦ Thoroughness of safety precautions and waste disposal methods
- Latent Print Development (30 points):
◦ Quality and clarity of developed latent prints
◦ Effectiveness of the lifting technique
◦ Minimal background interference or damage to the evidence
- Comparison and Analysis (30 points):
◦ Accuracy of the comparison between latent and known prints
◦ Justification of conclusions based on observed matches or exclusions
◦ Proper documentation of the comparison process
- Presentation (20 points):
◦ Clarity and organization of the presentation
◦ Effective communication of the method, results, and conclusions