Developing a method for determination of origin of fuels used as accelerator in arson cases

The destructive effects of fire are made difficult and complex to the fire investigation. The forensic fire investigator is charged with to search for evidence of ignitable liquids in the case of fire. The only viable way to identify ignitable liquid residues from the fire debris is to performed fire debris analysis based on verifiable scientific methods. İn this study, it was aimed to develop an unique analysis method by evaluating the use of a patented DNA product as a marker for identification of ignitable liquid residues, determination of origin and comparison/matching analyses. A positive identification for ignitable liquid residues as a result of fire debris analysis carried out in line with the standards does not mean that the detected ignitable liquid residues is an accelerator; negative identification also does not completely rule out the possibility of the presence of ignitable liquids. The compositions of the different classification ignitable liquids are similar to each other and may have many common compounds. The contamination, diminution, weathering, interference products, microbial degradation and acidification make it difficult to identify ignitable liquid residues. The GC-MS and PCR analyses of combustion residues of gasoline and diesel fuel samples which labeled and unlabeled by DNA marker were performed in this research. In the results of extraction and GC-MS analysis operations based on ASTM standards, n-alkanes, isoalkanes, cycloalkanes, C2-C4-alkylbenzenes, indane, methylindanes, naphthalene and methylnaphthalenes were detected. The aliphatic and aromatic profiles of the combustion residues were exhibited the related analytes and chromatographic patterns that relationally and consistently with the ignitable liquid classifications and comparison standards. The DNA marker was identified in the results of PCR analysis of combustion residues of the labeled gasoline and diesel fuel samples. It has been evaluated that the DNA marker can objectively enable the access to identify an ignitable liquid and to provide the informations about all stages of the supply chain through the PCR analysis of just a single sample containing any residues of the labeled ignitable liquid.