Investigação forense de incêndio: protocolo de identificação de vestígios acelerantes em espectroscopia no infravermelho

Abstract

There are numerous challenges faced by the Criminal Forensics in investigating a criminal act, and one of them revolves around obtaining satisfactory answers in the presence of a fire. This task becomes even more complex when the heat process consumes the examined object almost entirely, making it particularly difficult to determine the complete resolution of the problem, namely: culpable or intentional action? One promising avenue for a solution is the search for traces of fire accelerants, especially gasoline, diesel, and ethanol. To this end, the accelerants were recovered through fractional distillation of burned samples until isocombustion. An infrared spectrum was generated after the distillation step and compared to the spectrum of the corresponding accelerant in its natural state, thus obtaining a final qualitative response regarding the presence or absence of the fuel. The results were satisfactory, with the possibility of identifying and individualizing the type of fire accelerant in the samples. It should be noted as important differentials and advantages that the proposed protocol does not require super-specialization of the responsible technician nor highly sophisticated equipment. It is essential to infer, therefore, that the developed approach represents a promising asset in fire analysis and should be explored with the proper refinement of techniques.