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The sampling of ignitable liquids on suspects' hands.
Isabelle Montani1, Stéfane Comment, Olivier Delémont
1Institut de Police Scientifique, Ecole des Sciences Criminelles, Université de Lausanne, Lausanne-Dorigny, Switzerland. isabelle.montani@unil.ch
Forensic Science International
|December 4, 2009
Summary
Forensic investigators can now reliably collect ignitable liquid residues from arson suspects
Area of Science:
- Forensic Science
- Analytical Chemistry
- Arson Investigation
Background:
- Effective collection of ignitable liquid (IL) traces from arson suspects' hands is crucial for forensic investigations.
- Current swabbing methods lack simplicity, robustness, efficiency, and reliability, hindering accurate evidence collection.
- A validated procedure is needed to improve the collection of IL residues for subsequent laboratory analysis.
Purpose of the Study:
- To develop and evaluate a procedure for collecting ignitable liquid residues from the hands of arson suspects.
- To assess the applicability of various collection supports for gasoline traces on hands.
- To design and test a prototype sampling kit for efficient and contamination-free IL residue collection.
Main Methods:
- Sixteen different collection supports were evaluated for their efficiency in collecting gasoline traces.
- Passive headspace extraction using an activated charcoal strip (DFLEX device) coupled with gas chromatography-mass spectrometry (GC-MS) was employed.
- Background contamination from collection supports and collection efficiencies were assessed.
Main Results:
- Non-powdered latex gloves demonstrated the highest suitability for sampling ignitable liquid residues.
- Statistical analysis confirmed the superiority of non-powdered latex gloves over other tested materials.
- A prototype sampling kit, featuring a multilayer bag and latex gloves, was designed to prevent external and cross-contaminations.
Conclusions:
- Non-powdered latex gloves represent the most effective method for collecting ignitable liquid residues from suspects' hands.
- The developed prototype sampling kit offers an efficient and reliable solution for forensic arson investigations.
- This standardized procedure enhances the accuracy and integrity of evidence in arson cases.
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