[Analytical, toxicological and forensic aspects of drug-facilitated crimes: 10 years of experience]

Abstract

Although being a relatively old phenomenon, drug-facilitated crime has been well described over the past 20 years as being the administration without the knowledge of the victim of a psychoactive substance in criminal purposes (rape, robbery, theft, money extortion, even murder). Drug-facilitated crime involves also mistreatment of older people or children treated by their parents in order to obtain sedation. Drug-facilitated crimes are often difficult to solve mainly due to analytical issues. Since 10 years, we developed and improved specific methods using LC-MS/MS (benzodiazepines, neuroleptics) and GC-MS/MS (GHB, cannabis) to detect the drugs involved in such crimes. After the intake of a low dosage of a particular drug, those methods allow to detect the analyte of interest up to 3-5 days in blood, 10-15 days in urine, and more than 1 year in hair. In drug-facilitated crime cases, blood and urine are frequently collected too late, more than 12 h after the drug intake and in some cases with a delay greater than 48 h after the event. Thus, the most used molecules are undetectable by the techniques classically used in a laboratory of biology. Moreover, a "good" compound that can be used to commit a drug-facilitated crime usually possesses a short elimination half-life and amnesic properties, so that the victim is less able to accurately recall the circumstances under which the offence occurred. The recent progress in analytical toxicology, particularly for laboratories working in the field of forensic toxicology, permits to elucidate many cases of drug-facilitated crimes. Heaven to the introduction of the sequential analysis of hair and the use of sophisticated analytical techniques such as tandem mass-spectrometry for the toxicologist to bring the scientific proof to the applicant authorities in the description of the criminal act and to confuse the offender. The author presents the results of 583 presumed cases of drug-facilitated crimes analyzed by his laboratory specialized in forensic toxicology. One hundred and seventy of those cases were confirmed by the analyses of the blood and/or the urine and/or hair, in which molecules frequently encountered, were identified.