Abstract During vertebrate decomposition, a purge of nutrient‐rich fluids enters the surrounding soil producing a localized nutrient hotspot. The composition of microbial communities at the soil surface is known to predictably change in response to this influx of decomposition fluids over time. However, the depth to which these compositional changes permeate the soil near a decomposing human cadaver and whether specific microbial members exhibit spatial responses to aboveground decomposition both represent significant knowledge gaps. In this study, we longitudinally sampled forest soils adjacent to decomposing human cadavers and from nearby control sites in 2 cm increments to a depth of 10 cm. Soil samples were collected during purge, post purge, and the dry remains stage of decomposition over three seasons at Sam Houston State University's Southeast Texas Applied Forensic Science facility. We detected season‐dependent microbial community responses in the upper 0–4 cm of soils adjacent to decomposition fluids. On average, microbial community diversity decreased and community composition became increasingly different in comparison to nearby control soils. Cadaver soils remained impacted for the duration of the 4.5‐month spring trial and 1.5‐month summer trial. Terriglobus , Acidisoma , Ignatzschineria , and Pandoraea may represent forensically informative biological markers, as they significantly increased in response to decomposition. We observed a more limited, yet still detectable response in the lower 6–10 cm of soil. In addition to improving our understanding of decomposition ecology, we anticipate that incorporating these findings into forensic investigations could help strengthen postmortem interval model estimation and better inform investigative sampling practices.
Abstract Adhesive tapes recovered from crime scenes frequently function as dual‐purpose forensic substrates, simultaneously bearing latent fingermarks and touch DNA, yet their removal from porous surfaces often results in ridge distortion and loss of biological material. This study evaluated a solvent‐assisted tape separation protocol using a dichloromethane/ethyl lactate mixed solvent to enable effective tape removal while preserving both fingermark and DNA evidence. A 2:8 (v/v) dichloromethane/ethyl lactate formulation (DCM/EL_28) was identified as the optimal solvent condition, exhibiting minimal substrate damage and superior adhesive control. When applied to three common commercial tapes adhered to corrugated cardboard, DCM/EL_28 consistently produced well‐defined latent fingermarks with higher minutiae counts and AFIS‐derived similarity scores than two commercially available release agents, Un‐Stick and PIC 10, which showed variable ridge distortion or severe adhesive disruption. Following fingerprint development, DNA was successfully recovered from all tape samples, with the majority yielding complete or near‐complete STR profiles containing a high proportion of the alleles expected from the corresponding donor reference profiles. This proof‐of‐concept study demonstrates the feasibility of using the DCM/EL_28 mixed‐solvent protocol for tape separation while preserving fingermark and DNA evidence under the controlled experimental conditions evaluated. These findings provide a basis for further validation using a broader range of substrates, tape types, aging conditions, and casework‐relevant samples before its potential application in routine forensic practice can be established.
Abstract Post‐blast explosive residue analysis is crucial for forensic investigations, yet evidentiary value is often limited by sampling efficiency rather than instrumental sensitivity. This study investigated the recovery behavior of 2,4,6‐trinitrotoluene (TNT) under field‐realistic detonation conditions to improve sampling strategies through data‐driven modeling. Controlled TNT detonations were conducted at a secured site with bomb disposal experts and crime scene investigators. Residues were collected via swab sampling from metal, wood, and polyester surfaces placed 1–3 m from the blast center. Swabs were pre‐wetted with methanol, isopropyl alcohol, or acetonitrile, and samples were analyzed using semi‐quantitative LC–MS/MS. The study evaluated how surface material, solvent choice, and distance influence recovery using statistical comparisons and supervised machine learning. Results revealed a clear dependence on surface material; metal yielded stronger, more consistent TNT signals compared to the lower and more variable recovery from wood and polyester. Acetonitrile generally showed higher extraction efficiency, though performance varied by surface. As expected, recoverable TNT decreased significantly with distance. A Support Vector Regression (SVR) model successfully reproduced these experimental trends, providing stable predictions that account for non‐linear relationships between variables. These findings demonstrate that field conditions are decisive in residue recovery. Integrating experimental data with machine learning offers a practical method for estimating relative TNT recovery, providing evidence‐based guidance for sampling decisions during time‐sensitive post‐blast forensic investigations.
Abstract The use of UV‐C imaging for the detection of latent fingermarks has been reported since the 1970s; however, widespread adoption has been limited due to health and safety concerns as well as its possible detrimental effects on DNA evidence. Semi‐porous substrates may not be suitable for processing with methods recommended for porous or non‐porous substrates. This study evaluated the effectiveness of UV‐C imaging within the full spectrum imaging system (FSIS‐II) for the detection of latent fingermarks on semi‐porous substrates. Phase 2 laboratory trials and Phase 3 pseudo‐operational trials were conducted to assess fingermark quality across different donors, substrates, aging periods and depletion series with an enhancement sequence of UV‐C, UV‐A, cyanoacrylate (CA) fuming, UV‐C, UV‐A and black magnetic powder. The use of UV‐C and UV‐A imaging prior to CA fuming was ineffective. CA fuming produced relatively few high‐quality fingermarks across all variables; however, subsequent UV‐C examination increased the detection rate by up to tenfold in Phase 2 trials and fourfold in Phase 3 trials, due to enhanced scattering of UV‐C light by the CA polymer. The use of UV‐A marginally increased the number of detected marks after CA fuming. Based on effect sizes, all variables were statistically significant, with the enhancement technique exerting the greatest influence on fingermark quality. Similar trends were observed for the Phase 3 pseudo‐operational trial. This study highlights UV‐C imaging after CA fuming as one of the most effective processes for the detection of latent fingermarks on semi‐porous surfaces when dye staining is not possible.
