Long-Term Detection in Hair of Zolpidem, Oxazepam and Flunitrazepam in a Case of Drug-Facilitated Sexual Assault

Drug-facilitated sexual assault (DFSA) cases are pretty common in forensic toxicology. In this case report, a 56-year-old female tourist claimed to have been sexually assaulted by five men after having had a drug-spiked alcoholic drink. Urine samples were collected at 38, 44 and 45 h after the alleged rape. After 7 months, hair strands (28 cm in length) were also sampled to perform the segmental hair testing. The urine samples and decontaminated hair segments were tested for different groups of basic, acidic and neutral substances (γ-hydroxybutyrate or GHB, Z-drugs, barbiturates, benzodiazepines, hypnotics, antipsychotics and drugs of abuse). Gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry methods were applied for the qualitative and quantitative analyses. Toxicological analyses performed on the urine samples showed inconclusive findings. Zolpidem, flunitrazepam and oxazepam were detected in the hair segments corresponding to the time frame of the alleged assault. The endogenous levels of GHB were detected along the hair shaft. No drugs were detected in the proximal and distal hair segments or in washing solutions. This DFSA case demonstrated that the segmental toxicological analysis of hair, even when performed 7 months after the sexual assault, can provide evidence consistent with a single exposure to psychoactive drugs, at the time of the offense.