Found 3 results
Open Access
Article
15 August 2025Integrating DNA and Chemical Profiling to Trace Illicit Drug Manufacture and Distribution
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.
Open Access
Article
28 July 2025Investigating Touch DNA Success Rates in Vehicle Sites for Hit-and-Run Casework
This study evaluated the effectiveness of Touch DNA recovery from four key vehicle contact points—steering wheel (SW), gear shift (GS), interior door handle (IDH), and exterior door handle (EDH)—in the context of hit-and-run forensic casework. 1769 samples were collected from 359 vehicles processed between 2020 and 2023. Statistically significant differences were observed in the quantity and quality of DNA recovered across these sites (p < 0.05). The steering wheel yielded the highest DNA success rates, followed by the gear shift, whereas the exterior and interior door handles demonstrated substantially lower recovery efficiency. These findings underscore the critical role of strategic sampling site selection in maximizing evidentiary outcomes. The results support prioritizing the steering wheel and gear shift as primary targets for DNA collection in vehicle-based investigations. The study highlights the practical utility of Touch DNA in linking individuals to vehicular crimes and calls for further research into alternative sampling techniques and contamination control measures to optimize forensic DNA recovery protocols in real-world hit-and-run scenarios.
Open Access
Article
20 March 2024Development and Validation of a Novel 29-plex STR Multiplex System for Legal and Forensic Science
Short tandem repeat (STR) analysis is the gold standard method in forensics for personal identification and paternity testing. Researchers have been working on developing novel multiplex systems containing more STRs for database construction and improvement of personal identification ability. This study's six-dye multiplex amplification system contained 29 autosomal loci, Y-indel, and Amelogenin. System optimization and performance measures were out according to the recommendations of the Scientific Working Group on DNA Analysis Methods, including PCR condition, sensitivity, mixture, inhibitor, species specificity, reproducibility, precision, stutter, concordance, and population study. The results showed that the complete profile was obtained with 125 pg of DNA input in a sensitivity study and a mixture ratio of 1:4. The full profile was observed with a hematin concentration ≤ 125 μmol/L, hemoglobin ≤ 200 μmol/L, EDTA ≤ 1.5 mmol/L, humic acid ≤ 1.5 μg/μL, indigo ≤ 12 mmol/L, and calcium ≤ 6.0 mmol/L. Meanwhile, the system also showed reasonable species specificity. Population genetic results showed the high performance of this panel with high informative and polymorphic loci, which possessed high estimates of the combined power of discrimination (1–7.16 × 10−35) and the combined power of exclusion (1–1.98 × 10−12) in southern Han Chinese populations.
