The combined analysis of hair samples with fly larvae for the forensic identification of skeletonized human remains

Purpose: In the present work, we report the combined use of hair and fly larvae samples as a valuable approach for obtaining additional toxicological evidence in cases of skeletonized corpses. In highly decomposed human remains, the absence of conventional biological specimens (e.g. blood, urine, and organs) requires alternative matrices to base the forensic investigation upon. However, it is challenging to find the most suitable medico-legal approach in these cases. Methods: Hair and fly larvae samples were collected from two independent cases and processed by solid phase extraction using a similar procedure. Analyses were performed using liquid chromatography tandem mass spectrometry. Results: Two anticonvulsants were found in the samples but in a different pattern: phenobarbital in case 1, and phenobarbital in association with phenytoin in case 2. Conclusions: The results of this toxicological approach combining two different samples, hair and larvae, in addition to circumstantial and autopsy findings, proved to be paramount in the medico-legal assessment of the cases herein described, leading to the successful identification of the subjects by DNA analysis. We thus hope that the approach and findings reported in this work contribute to the growing entomotoxicology science and its applicability to real complex forensic cases, especially considering that, to the best of our knowledge, this is the first article describing the determination of phenytoin in insects for this purpose.