Detection of Drugs in Drug Facilitated Sexual Assault (DFSA) Cases Using Onsite Screening Devices: A Forensic Review

Drug Facilitated Sexual Assault (DFSA) has now become the most prevalent crime in the today’s scenario. It is an offence in which criminal uses the drug to influence the victim for committing assaults, rape, murder, etc. It is a kind of violent act in which the individual is incapacitated with certain mind altering substances resulting in impairment of victim’s ability to respond and prevent her from remembering the assault. A wide variety of Central Nervous System (CNS) depressants namely flunitrazepam or rohypnol, GHB (Gamma Hydroxy Butyric Acid), over the counter and prescription drugs involving benzodiazepines, non benzodiazepines hypnotics and sedatives like zolpidem, zopiclone and other psychotropic substances like ketamine, etc., are introduced secretly into the drinks or food material of the victim without eliciting any noticeable taste or colour change. Since benzodiazepines are most commonly abused in these crimes, much difficulties arise in their detection firstly due to their commercial availability in large numbers and secondly because they get rapidly metabolized into multiple forms.

These cases are therefore remains underestimated and hence not being reported to the police personnel. Detection of these drugs being a serious challenge in the field of toxicology because routine analytical procedures cannot be opted for their analysis hence a highly rapid, sensitive and specific technique for their detection is required. Immunoassay techniques are used widely for detection of these drugs due to their rapidity, flexibility and ability to facilitate a preliminary indication of the presence of a particular drug or an array of drugs in the matrix analyzed. The testing is based on binding of an antibody, specific for a particular drug or a drug group and its label that will be used later as a part of complex formed between antigen and antibody detected by means of some fluorescence. The technique mainly functions on the basis of competitive binding between the antibody and the drug antigen. These can be used onsite for the detection of the drug. This binding between the two depends more on a typical immune response generated when the antibodies in the biological tissues combines with the antigen and neutralize them. In the present paper an attempt has been made to consolidate the information regarding the onsite drug detection devices available for the qualitative detection and identification of drugs.