Detecting date rape

A major new forensic science research project has been produced to aid detection of drug facilitated sexual assaults – ‘date rape’ – and non-accidental poisoning of children. Damian Small reports.

Using analytical techniques coupled with new technologies, Professor David Cowan and his team from the Department of Forensics Science and Drug Monitoring, King’s College London (KCL), aim to fill a gap in forensic science capabilities for drug detection.

“These are two important and growing types of serious crime where vital forensic evidence may be difficult or impossible to obtain using current methods of detection,” said Professor Cowan. “Our work addresses an important gap in forensic science capabilities for drug detection by undertaking the development of new ultra-sensitive laboratory techniques to detect drugs and their breakdown products in the body at extremely low levels – less than one part in ten billion – in tiny samples of blood or urine,” he explained.

Furthermore, the project will use methods that will be able to detect more recently established drugs such as Ketemine which, because of their metabolic make up, current forensic techniques are not set to detect.

Large intoxicating single doses of substances that are fast-acting and disappear from the body quickly characterise the date rape drug. In child abuse cases, chronic administration is more typical but the sample volume is much less. Presentation of either type of case is often delayed which means that sensitivity of the analytical technique is crucial. This is very different from most cases of post-mortem toxicology where the drug concentration is expected to be large.

Explaining the reasons for the project, Professor Cowan said that with state-of-the-art technologies available today, his team thought it was time to revisit some older problems in detecting drug facilitated sexual assault.

“Currently, there is very little forensic evidence of drug administration in many such cases, mainly because incidents are often reported 12 hours, a day or even 36 hours after the alleged assault has taken place, when very little of the drug will remain in the victim’s body. Similarly, late samples are often collected from children where suspicion of non-accidental poisoning may only come to light after routine medical evaluation has been performed,” explained Professor Cowan.

He used the example of child abuse cases involving drug administration, where the experts may pursue other avenues before deciding that it could be a toxicology case, thus resulting in a delay in collecting the necessary samples and by which time the evidence may have disappeared.

“In addition,” he added, “blood and urine samples collected from babies and young children are usually very small, and analysis may only be performed on the small samples that remain after routine medical laboratory diagnostic investigations have been completed. Unfortunately, current forensic techniques are poorly established for the detection of some prescription-only medicines, such as anti-depressants and hypnotics.”

Moreover, Professor Cowan explained that certain illicit drugs like Ketamine, Flunitrazepam and the naturally made substance Gamma Hydroxybutyris (GHB) acid are not generally included in routine forensic and clinical drug screening procedures. Improving detection of these substances in drug-induced sexual assault is the key theme of Professor Cowan and his team’s work.

The team brings together knowledge of microseparations (to separate the myriad of substances present in urine samples), mass spectrometry (for unequivocal identification of substances in minute amounts), toxicology and drug metabolism (to know what to look for) and chemistry (for chemical modification to enhance sensitivity).

“The team’s expertise in microseparation is fundamental to this new approach and obtaining this goal,” Professor Cowan explained.

“Large improvements in detection can be achieved using ultra efficient separation a