Integrating DNA and Chemical Profiling to Trace Illicit Drug Manufacture and Distribution

Abstract

Illicit drug materials represent a valuable but underutilized source of forensic intelligence. While chemical profiling is routinely used to trace drug composition and origin, the recovery of trace DNA offers the potential to link these substances directly to individuals involved in their manufacture and distribution. This study evaluates the forensic utility of integrating DNA profiling with chemical analysis to improve source attribution across different drug formulations. Pharmaceutical-grade simulants in the form of capsules, tablets, and powders were handled by volunteers under controlled deposition scenarios. DNA was recovered using moistened cotton swabs, extracted via automated silica-based workflows, and analyzed using STR profiling. In parallel, chemical fingerprints were generated through GC-MS and LC-MS, with sample classification based on retention time and mass spectral data. Capsules yielded the highest DNA recovery (median: 310 pg), followed by tablets (230 pg) and powders (18 pg), with single-source STR profiles obtained in over 85% of capsule and tablet cases. Chemical profiling achieved 85% accuracy for capsules, 78% for tablets, and 65% for powders. When integrated, the combined approach significantly outperformed individual methods, achieving classification accuracies of 97% for capsules, 85% for tablets, and 72% for powders (p < 0.01). These findings demonstrate the enhanced evidentiary value of dual profiling, particularly in cases involving degraded or limited DNA. The proposed framework supports a more comprehensive forensic strategy, enabling biological and chemical linkage of drug materials to persons of interest and manufacturing sources. This integrative approach offers critical advantages for law enforcement and prosecution in disrupting drug trafficking networks.