Fatal Rectal Injection of 3-MMC in a Sexual Context: Toxicological Investigations Including Metabolites Identification Using LC-HRMS.

The dead body of a 59-year-old man was found at his home by his father. The subject was naked in the corridor, wearing a black hood and a collar around the neck where a dog leash was attached. An empty syringe was discovered in the decedent's rectal vein. The autopsy revealed marked asphyxia signs with no indication of violence or trauma. Femoral blood, urine and hair (4 cm, brown) were collected and submitted for comprehensive toxicological investigation. Initial screening did not indicate the presence of ethanol or any other over-the-counter or prescription pharmaceuticals. Routine toxicology screening by liquid chromatography-tandem mass spectrometry (LC-MS-MS) tentatively identified only the cathinone stereoisomer(s), 3-methylmethcathinone (3-MMC) or mephedrone. Analysis by gas chromatography-MS to distinguish between the isomers revealed the presence of 3-MMC, which was subsequently quantified by LC-MS-MS. Femoral blood and urine concentrations were 1,437 and 16,733 ng/mL, respectively. In 4 × 1-cm hair segments, 3-MMC was detected at <10 pg/mg (limit of quantification). Further analysis by liquid chromatography-high-resolution mass spectrometry (LC-HRMS) allowed the identification of two metabolites in both blood and urine: desmethyl-3-MMC and hydroxyl-3-MMC. The pathologist established the cause of death in this case as acute 3-MMC poisoning in the context of ChemSex.