The Forensics Mentors Institute

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Drug Facilitated Sexual Assault- Michael Robertson, Ph.D.

In recent years, the detection and conviction of individuals involved in drug-facilitated sexual assault (DFSA) has risen. Whether this is due to an increase in drug-facilitated sexual assault per se or an increase in awareness and delectability is not known. What is known however is that the range of drugs used to commit such crimes is broad and certainly beyond just Roofies (Rohypnol) and GHB (gamma-hydroxybutyric acid).

Drugs commonly detected in cases of alleged DFSA include ‘recreational drugs’ such as alcohol, marihuana, cocaine and amphetamines, as well as those drugs capable of producing rapid drowsiness, amnesia in addition to a poor ability to detect. These include the benzodiazepines alprazolam, triazolam and temazepam, also GHB and GBL (gamma-butyrolactone).

Due to large range of drugs detected in cases of DFSA, often in combination with a delay in specimen collection of up to 72 hours, simple screening procedures are often inappropriate techniques. Unfortunately they are however the least expensive and most frequently used, particularly in the hospital setting. This type of procedure will in most cases not detect many of the frequently used benzodiazepines, nor is it able to detect GHB or GBL.

All DFSA cases should be handled as an investigation, looking for as many drugs as possible and as selective and sensitive as possible, given the low concentration of drugs detected in most cases.

Specimen collection should take place as soon after the alleged incident as possible and consist of urine and blood. Rapid collection will assist in interpretation and detection of drugs such as GHB.

The following are further recommendations: alcohol, the drug most often detected in cases of DFSA should be determined if specimens are collected within 10 hours. Benzodiazepines should be analyzed for using gas chromatography / mass spectrometry techniques (GC/MS) in addition to immunoassay techniques to give the greatest sensitivity. A determination of the presence of GHB should also be employed, particularly if vomiting is documented as having occurred. A general drug screen for other drugs such as ketamine, amphetamines, barbiturates, opiates etc. should also be performed to rule out the use of prescription or other non-prescription medications.

Interpretation of results should be done carefully, by a qualified and experienced forensic toxicologist who is aware of the issues and the testing performed during the investigation. The three aspects of an investigation that requires the most attention and are commonly overlooked are: collection of specimens; extensive analyses; and informed interpretation.