A multi-modal mass spectrometry approach for the detection and mapping of date rape drugs in fingermarks †

Although drug facilitated sexual assault (DFSA) is an old issue, current statistics on the frequency of this crime have led to growing concerns. As these drugs are metabolised very quickly, toxicological evidence from biological fluids, corroborating the victim's statement, is challenging to recover, especially with late reports. We are proposing an additional method involving the analysis of the victim's fingermarks recovered at the scene(s) of the crime, which may contain the parent drug and its metabolite. As a case study, a multi-modal mass spectrometry-based approach has been developed and explored to detect and image both risperidone and its pharmacologically active metabolite, paliperidone, after contamination of a fingertip at very low concentrations and deposition of a fingerprint on a surface. In particular Matrix Assisted Laser Desorption Ionisation Mass Spectrometry Imaging (MALDI MSI), Desorption Electrospray Ionisation Mass Spectrometry Imaging (DESI MSI) and Soft Ionisation by Chemical Reaction In Transfer, (SICRIT®) have been used in different combinations to both detect the drugs and reconstruct the fingerprint ridge pattern; this approach enables the simultaneous provision of both chemical information (circumstances surrounding the crime) and biometric information. A forensic operational scenario has also been simulated whereby the contaminated fingerprint is deposited on paper and enhanced with a routine fingerprint enhancement technique prior to analysis via mass spectrometry imaging. Overall, our investigation indicates that this additional approach is feasible and is worth exploring further.

Detecting Date Rape Drugs: New Method Uses Fingermarks for Evidence

What is it about?

The study explored a multi-modal mass spectrometry approach for detecting and mapping date rape drugs in fingermarks. It specifically focused on the detection of risperidone, a benzisoxazole used as an antipsychotic, which has also been misused in drug-facilitated sexual assault (DFSA). The approach aimed to address the challenge of rapid metabolism of DFSA drugs, which often results in a lack of toxicological evidence. Using mock-up drug- and metabolite-contaminated fingermarks, the study aimed to provide insights into the feasibility of detecting these species even days after the crime as preliminary data suggest they persist in this specimen. The methodology involved using mass spectrometry imaging to analyze the fingermarks for risperidone and its metabolite paliperidone. This technique was evaluated for its potential to provide valuable intelligence, either by narrowing down suspects or by corroborating victims’ claims. The study successfully demonstrated the feasibility of detecting such substances in fingermarks, presenting a potential non-invasive method for evidence collection in DFSA cases.

Why is it important?

This study is significant as it presents a fundational and potentially game chaning approach to detecting and mapping date rape drugs in fingermarks using multi-modal mass spectrometry. By addressing the challenge of detecting rapidly metabolized drugs in cases of drug-facilitated sexual assault (DFSA), the research offers a potential method for gathering solid physical evidence, which is often lacking in these cases. Though it still requires validation with controlled samples from donors, for example, individuals taking this type of prescribed medication, this advancement has the potential to improve the investigation and prosecution of DFSA cases by providing critical evidence that supports victims' claims and narrows down suspect pools. Additionally, the study's focus on risperidone, a drug with dual use in both medical and illicit contexts, underscores the method's applicability to a range of substances used in DFSA.

Key Takeaways:

1. Novel Detection Method: The research successfully explores the use of multi-modal mass spectrometry to detect risperidone and its metabolite paliperidone in fingermarks, offering a new avenue for identifying DFSA drugs that are otherwise challenging to detect due to rapid metabolism.

2. Evidence Collection Enhancement: By leveraging the potential of fingermarks as a biological specimen, the study provides a non-invasive means to gather corroborative evidence in DFSA cases, which could significantly aid legal proceedings and victim support.

3. Versatile Application: The method's ability to detect a commonly prescribed antipsychotic drug highlights its potential adaptability for other DFSA drugs, suggesting broader implications for forensic science and public safety.