Journal of forensic sciences最新文献

Document shredding remains a common method for destroying sensitive information, creating significant challenges for forensic investigators seeking to recover such materials as evidence. This paper addresses shredded document reconstruction through a stochastic optimization approach inspired by Markov chain Monte Carlo (MCMC) methods. Unlike traditional approaches relying on physical edge matching—suitable for hand-torn documents but computationally prohibitive for cross-cut shredding—our method evaluates visual content matches through edge compatibility metrics. We develop a specialized acceptance criterion balancing exploration of diverse configurations with exploitation of promising solutions. The method employs gamma distribution modeling of edge deviations with maximum likelihood parameter estimation, providing an adaptive framework responsive to reconstruction progress. Through evaluation with over 1100 document instances spanning typed text, handwritten notes, photographs, and mixed-content materials, we demonstrate robust performance across diverse document types. Empirical comparisons reveal that while simulated annealing (SA) and genetic algorithms (GA) achieve only marginal cost reductions (1%–13%), our approach successfully reconstructs documents that these standard metaheuristics cannot solve. The algorithm handles intermixed fragments from multiple documents—common in forensic casework—with performance analysis showing content-rich regions assembling faster than uniform areas. Validation on physically shredded documents from the DARPA Shredder Challenge confirms practical utility where traditional methods fail. For complex reconstructions, our semi-automated approach incorporates human guidance at intermediate stages, reducing computation time while maintaining accuracy. This research advances forensic document examination capabilities, offering a flexible framework adaptable to various document types encountered in investigative practice.

Lysergic acid diethylamide (LSD) and analogs are psychedelic drugs commonly submitted to forensic chemistry laboratories. These drugs are often present on items of evidence at low concentrations, requiring sensitive analyses to positively identify their presence. The injection port of a gas chromatograph (GC) plays an important role in vaporizing and transferring substances to the column for separation and subsequent detection. The consumables in the inlet, specifically the liner, can influence the abundance and chromatography of compounds being analyzed. Twelve liners with varying geometries, packing materials, and deactivation chemistries were assessed by analyzing a mixture of eight LSD-related compounds and comparing the average peak areas. Liners containing packing materials yielded significantly higher peak areas as compared to those without. The geometry of the liner played a smaller role and affected results only with one deactivation when glass wool was not present. Base deactivation improved peak area when compared to standard and Topaz deactivation in straight liners with packing. Authentic samples were analyzed on liners with varying deactivation chemistries to determine the effect over a run of seven replicates of 10 street samples (70 sample injections). Peak area with base-deactivated liners and liners with standard deactivation remained consistent over time, whereas the liner with Topaz deactivation decreased in peak area 52–68% after the initial injection and demonstrated a decrease in peak area of 30–54% from the first injection to the final injection.

Latent fingerprints constitute a cornerstone of forensic identification. However, their visualization is a technical challenge—highly dependent on the nature of the surface from where fingerprints are collected, environmental exposure, and the detection agent applied. Herein, we report the preparation of a new compound, [5-benzylidene-4-oxo-2-thioxo-1,3-thiazolidin-3-yl] acetic acid (compound 3), by Knoevenagel condensation and characterization by ¹H NMR and FTIR. Its ability to develop latent fingerprints was systematically assessed on a wide variety of surfaces, including marble, plywood, glass, plastic sheet, silver foil, human skin, rubber gloves, and thermocol. Theoretical studies (density functional theory and molecular docking analyses) explored interactions with serine, highlighting the role of specific binding interactions in fingerprint development. This innovative approach, blending synthetic chemistry, spectroscopic techniques, and theoretical studies, paves the way for the development of new latent fingerprint agents in the future.

The present study expands upon previous studies by employing attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy as a nondestructive technique for estimating the time since deposition (TSD) of blood traces on common fabrics and household items. Initial analysis showed substrate contributions; however, these did not affect the amide I and II bands specific to blood proteins in infrared spectra. A comprehensive statistical analysis was conducted which was evaluated using external validation; this was done to ensure that model predictions remain reliable and to prevent overfitting, which can be introduced by internal validation methods. To identify relatively recent bloodstains, a partial least squares discriminant analysis (PLS-DA) classification model was developed to effectively distinguish between blood samples aged on cotton and polyester for ≤72 and >72 h. The external validation of these binary models yielded average prediction accuracies of 92% for bloodstains on polyester and 94% for those on cotton. A partial least squares regression (PLSR) combined with a genetic algorithm (GA) was used for building regression models with R² prediction values of 0.86 and 0.85 for polyester and cotton, respectively. This proof-of-concept study demonstrates that ATR-FTIR spectroscopy combined with advanced chemometrics enabled estimation of the time since deposition (TSD) of blood traces on cotton and polyester fabrics. Although the results are promising, the study involved a small number of donors and limited surface types; therefore, additional future research is needed to determine its broader applicability to a wider range of donors and surfaces.

This case report presents a rare incident of sibling incest resulting in pregnancy, occurring within a context of paternal neglect and inadequate parental supervision. A 14-year-old boy, after unsupervised exposure to pornographic content on his father's mobile device, engaged in sexual intercourse with his 15-year-old sister. The case highlights the psychological and developmental risks posed by early and unregulated access to sexually explicit material. It also underscores the diagnostic, ethical, and legal challenges in the detection and forensic evaluation of intrafamilial sexual abuse. This report emphasizes the urgent need for preventive strategies, including parental controls, digital literacy training, and age-appropriate sexual education.

One of the United States Food and Drug Administration's (FDA) National Forensic Chemistry Center (NFCC) international mail facility (IMF) satellite laboratories received suspect light blue, round tablets debossed with “PERCOCET 5” on one side and half score on the other side. Although legitimate products with these characteristics contain acetaminophen and oxycodone, the suspect tablets examined in this study were found to contain caffeine by an FDA satellite laboratory. Based on the presence of this unlabeled ingredient and having markings that would indicate a controlled substance, the tablets were recommended for further analysis by NFCC's full-service laboratory. Preliminary analysis using liquid chromatography with mass spectrometric detection (LC–MS), the full-service laboratory confirmed the presence of caffeine and also determined that the tablets contained a nitazene-type compound. Qualitative method development using LC–MS permitted the ability to identify this compound as N-pyrrolidino protonitazene, while ruling out closely related compounds N-pyrrolidino isotonitazene and N-piperidinyl etonitazene. Quantitative method development using LC–MS determined that the tablets contained an average of 99 ± 16 μg N-pyrrolidino protonitazene per tablet. This finding is alarming considering that this compound reportedly has 25 times the potency of fentanyl. Although this is not the first time this nitazene analog has been reported, this case study adds additional information for identifying this compound. Since first being identified in these tablets, N-pyrrolidino protonitazene has been encountered with increasing regularity by this laboratory in other tablets with different colors, shapes, and markings. This compound has also been identified in tablets containing other drug substances.

Explosions involving primary explosives as the sole energetic material are very uncommon, since such compounds are typically used only to initiate main charges. This case report addresses an unusual blast at a civilian logistics facility, where primer compositions containing lead styphnate were present not as initiators but as the principal energetic charge. To investigate this rare scenario, postblast residues were collected from a cotton disc at the explosion epicenter and subjected to forensic chemical analyses. Tandem mass spectrometry (MS–MS) revealed the styphnate ion, while scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDS) identified lead-rich particles consistent with lead styphnate residues. Additionally, Pb–Ba–Sb–containing particles, characteristic of gunshot residue, were observed. The morphological characteristics of the particles indicate high-temperature formation and, together with their chemical composition containing Pb, Ba, and Sb, provide strong evidence of residues related to deflagration. These findings confirm that the explosion residues originated from a primary explosive, highlighting the forensic relevance of identifying such unconventional scenarios.