Forensic Science International[JOURNAL]
Sun
200 papers
KLINK: A program for kinship testing with pairwise linked STR markers.
Vigeland MD, Gilfillan S
Forensic Sci Int Genet · 2026 Jul · PMID 42401178 · Publisher ↗
We present KLINK, a free, user-friendly tool for forensic kinship testing that accommodates linkage between marker pairs and also advanced mutation models. This addresses a gap in existing software, which typically handl...
We present KLINK, a free, user-friendly tool for forensic kinship testing that accommodates linkage between marker pairs and also advanced mutation models. This addresses a gap in existing software, which typically handles either linkage or mutation modelling, but not both. In realistic simulations with up to 43 markers, our method captured nearly all linkage-related effects on the likelihood ratio, whereas ignoring linkage often resulted in substantial LR bias and reduced power to identify the correct relationship. The results indicate that KLINK is well suited for forensic kinship casework, both with standard kits of about 20 markers and with extended kits used in more challenging cases. The program is available both as a web application and as an R package, and does not require programming skills. Finally, as a separate companion to KLINK, we developed the interactive app Linkage Lab, for exploring LR behaviour and building intuition in kinship analysis with linked markers.
Data-driven methods allow prediction of utility of DNA rework.
Cammareri C, Wagenaar C, de Wit A … +6 more , Hoegen B, Nguyen L, Sjoukema P, Luijsterburg M, Ypma RJF, Benschop CCG
Forensic Sci Int Genet · 2026 Jul · PMID 42398372 · Publisher ↗
In forensic DNA casework, complex trace samples may benefit from rework procedures involving additional PCR replicates and lowered analytical thresholds. These procedures may strongly increase or decrease the likelihood...
In forensic DNA casework, complex trace samples may benefit from rework procedures involving additional PCR replicates and lowered analytical thresholds. These procedures may strongly increase or decrease the likelihood ratio (LR), simplifying decisions to be taken downstream. However, the procedures are resource-intensive. Decisions to pursue rework currently rely on laboratory guidelines and expert judgment rather than empirical evidence. This study aims to develop a model that predicts whether rework will yield a more decisive LR, defined as crossing the laboratory's reporting thresholds. To this end, we collected 2538 casework samples for which rework was performed and extracted features from the trace DNA profile and the initial LR calculation. An XGBoost classifier trained on these data demonstrated strong performance, achieving an area under the receiver operating characteristic curve (AUC ROC) of 91% and an accuracy of 82% on independent validation data (n = 121). However, a simple density-based model utilizing only a single feature, the initial log LR, performed nearly as good on the test set and comparable on the holdout set, with an AUC of 92% and an accuracy of 81%. When compared with assessments from 19 DNA experts on 23 cases, both models achieved an accuracy of 95%, compared to 72% for expert estimates. Experts frequently classified cases as uncertain (34%-66% success probability), whereas the models provided more decisive predictions. These results demonstrate that data-driven methods can enhance the efficiency and uniformity of forensic DNA workflows by providing evidence-based guidance for rework decisions, complementing expert judgment in resource allocation. In this application, the simpler model is preferred over more complex machine learning approaches due to its comparable performance and higher robustness and explainability.
Investigating interdisciplinary learning outcomes in a forensic science programme.
Lim XX, Low YN, Gan JS … +1 more , Tan WS
Forensic Sci Int Synerg · 2026 Dec · PMID 42395048 · Full text
Forensic science operates at the intersection of science and law and requires graduates who can integrate disciplinary knowledge while exercising critical judgement across complex investigative contexts. This study exami...
Forensic science operates at the intersection of science and law and requires graduates who can integrate disciplinary knowledge while exercising critical judgement across complex investigative contexts. This study examines self-perceived interdisciplinary learning outcomes among undergraduate and postgraduate students in a university forensic science programme, using Biggs' Presage-Process-Product model as a pedagogical framework to contextualise how curriculum design and active learning processes may support interdisciplinary competence. Across six academic semesters from 2022 to 2024, 260 students completed an 18-item survey adapted from Lattuca, Knight, and Bergom measuring Interdisciplinary Skills, Reflective Behaviour, and Recognizing Disciplinary Perspectives on a five-point Likert scale. Students reported the highest ratings in Interdisciplinary Skills (M = 4.33), indicating confidence in integrating knowledge across scientific and legal domains. Lower ratings were observed for Reflective Behaviour (M = 3.89) and Recognizing Disciplinary Perspectives (M = 3.83), suggesting more moderate perceived development in metacognitive and epistemological dimensions of interdisciplinary learning. Item-level analysis further showed that students felt capable of synthesising knowledge across fields but were less confident in evaluating disciplinary strengths and limitations or identifying gaps in expert reasoning. These findings suggest that active and practice-based pedagogies are associated with high self-perceived disciplinary grounding and integration but require more explicit scaffolding to foster critical awareness, epistemological reflection, and metacognitive development. By mapping empirical measurements onto established interdisciplinary learning outcomes, this study provides evidence-informed directions for strengthening interdisciplinary pedagogy in applied forensic science education.
Quantitative DNA/RNA fragmentation assays for estimating the time since deposition (TsD) of bloodstains.
He H, Mo X, Zhou Z … +4 more , Li Y, Wang Z, Zhao D, Sun Q
Forensic Sci Int Genet · 2026 Jun · PMID 42391882 · Publisher ↗
The time since deposition (TsD) of bloodstains can provide crucial information for forensic casework, yet reliable estimation methods remain limited. This study aimed to identify an optimal quantitative PCR (qPCR) approa...
The time since deposition (TsD) of bloodstains can provide crucial information for forensic casework, yet reliable estimation methods remain limited. This study aimed to identify an optimal quantitative PCR (qPCR) approach for bloodstain TsD estimation, analyze factors influencing nucleic acid stability, and construct human-applicable inference models. A total of 244 human bloodstain samples (238 for marker evaluation and model construction, and 6 [T1-T6] for independent validation) were prepared under different time points, temperatures, and substrates (grouped into two sample sets), together with 11 animal samples for primer species-specificity testing. Six candidate markers were initially selected from the literature and further screened based on LinRegPCR analysis, species-specificity tests, and standard-curve evaluation; their stability was then assessed using multiple reference-gene stability tools. Correlation analysis, linear regression, and curve fitting were used to construct and validate the models. Four qualified markers were retained, among which COX1 and 16S rRNA were confirmed to be human-specific. Under the conditions examined, short amplicons of the target genes exhibited expression stability comparable to that of conventional internal reference genes, providing, to our knowledge, the first experimental evidence for an assumption previously adopted without formal verification. Among the four qPCR-based quantification indicators compared, the same-marker relative expression ratio (RER) method showed the strongest correlation with TsD and reduced sex-related inter-individual variation. Nucleic acid stability was jointly affected by marker type, fragment length, storage time, temperature, substrate, and sex, with storage time being the dominant external factor. Eight models demonstrating superior performance were selected (two for Sample Set 1 at 25 °C, and six for Sample Set 2, with two per substrate across blood card, cotton swab, and gauze), all yielding R² > 0.6 for short-term (≤ 2 months) and R² > 0.8 for long-term (up to 2 years) samples, with all mean absolute percentage errors (MAPEs) below 30% on T1-T6. The same-marker RER method is thus proposed as an effective qPCR-based approach for forensic bloodstain TsD estimation.
Ensaya: An ensemble age model for prediction of chronological age in adolescents and young adults.
Stenløkk K, Dahlberg PS, Rolseth V … +7 more , Bernitz H, Gamieldien MY, Gholmieh MN, Robinson L, Saadé A, Uys A, Bleka Ø
Forensic Sci Int Genet · 2026 Jun · PMID 42391881 · Publisher ↗
DNA methylation-based models for chronological age estimation have, for over a decade, been among the most important methods for age prediction in humans. While large-scale data have enabled the development of numerous m...
DNA methylation-based models for chronological age estimation have, for over a decade, been among the most important methods for age prediction in humans. While large-scale data have enabled the development of numerous models, their accuracy varies substantially depending on choice of machine learning algorithm, pre-processing pipeline, age range, tissue type, and population characteristics. Accurate age estimation in adolescents and young adults is particularly relevant in legal, investigational, and biomedical contexts. Here, we systematically evaluated blood-based DNA methylation age predictors in individuals aged 12-25 years and developed Ensaya (Ensemble age model for prediction of chronological age in adolescents and young adults), an ensemble model optimized for this age range. We assembled a validation dataset of 687 whole blood or peripheral blood mononuclear cell samples from 12 cohorts, profiled using Illumina 450 K, EPIC, and EPIC v2 arrays. We compared existing clocks and assessed robustness across cohorts, platforms, normalisation procedures, technical replicates, sex, and circadian timing. Among individual models, PAYA, cAge, and Garma showed the strongest performance and were combined into the Ensaya ensemble. In validation, Ensaya achieved improved accuracy, with a median absolute deviation of 0.79 years and a mean absolute error of 1.04 years, along with reduced age-dependent bias. It also demonstrated high technical reproducibility and stable performance across platforms and normalisation methods. These findings show that ensemble-based modelling improves age estimation in adolescents and young adults, supporting Ensaya as a practical blood-based predictor.
Technical note: Development of a UHPLC-MS/MS method for the analysis of hCG and IGF-I from dried blood spots: A preliminary study.
Tespio G, Pelletti G, Pascali JP … +3 more , Demey E, Limaj X, Vinh J
Forensic Sci Int · 2026 Jun · PMID 42385550 · Publisher ↗
Two of the most used hormones in sport, included in the WADA list of banned molecules, are human chorionic gonadotropin (hCG) and insulin-like growth factor (IGF-I). Male athletes may use pharmaceutical preparations of h...
Two of the most used hormones in sport, included in the WADA list of banned molecules, are human chorionic gonadotropin (hCG) and insulin-like growth factor (IGF-I). Male athletes may use pharmaceutical preparations of hCG to stimulate the production of testosterone before competition and IGF-I to stimulate muscle protein synthesis, promote glycogen storage, and improve lipolysis. Dry matrix microsampling and dried blood spots (DBS) are very promising strategies to improve current doping control activities, as they can lead to a significant improvement in compound stability, the simplification of sample collection and pre-analytic phases, the facilitation of their automation and a reduction of the risks of sample contamination and tampering. In this study, a protein extraction protocol from DBS, specifically hCG and IGF-I, was developed. Through the testing of various extraction solvents and subsequent analysis by Qubit fluorometry and nanoLC-MS/MS, we established an effective protein extraction procedure from DBS, specifically targeting hCG and IGF-I. The nanoLC-MS/MS bottom-up proteomic study reported a good protein extraction protocol from DBS, demonstrating good reproducibility and abundance related to the peptide sequences of hCG and IGF-I detected.
A novel and robust deep learning model for sibling firearm matching.
Arin E, Yetik IS
Forensic Sci Int · 2026 Jun · PMID 42385549 · Publisher ↗
In this paper, our goal is to develop a novel and robust method for firearm sibling matching from cartridge-case head (in specific firing pin region) photometric stereo imagery. We employ a dataset of unprecedented scope...
In this paper, our goal is to develop a novel and robust method for firearm sibling matching from cartridge-case head (in specific firing pin region) photometric stereo imagery. We employ a dataset of unprecedented scope compared to prior literature, incorporating genuine real-world case work, including cartridge cases fired from aged, worn, or deliberately modified firearms across different time periods, making it the most challenging setting. Methodologically, the study introduces a triplet-loss framework with semi-hard negative mining and an explicit margin term, combined with a pre-contrastive loss-an approach not previously explored in this domain. Performance is benchmarked against a deep model trained using pure contrastive loss as a most powerful method up to now used in this area. Our proposed model clearly outperforms with a large margin. Within first 20 candidates of models as siblings in test set, our model reaches to 90% of success while contrastive model 52%. Overall, the proposed study presents the strongest contribution in the literature on cartridge-case sibling matching, both in dataset realism and methodological advancement.
Interpol review of forensic paint, tape, and glass evidence 2022-2025.
Almirall J, Trejos T
Forensic Sci Int Synerg · 2026 Dec · PMID 42381832 · Full text
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Changes in C-reactive protein levels over time in high-temperature environments using postmortem blood.
Shim YT, Kim HG, Park H … +3 more , Lee YM, Kim TG, Won Y
Forensic Sci Int · 2026 Jun · PMID 42378876 · Publisher ↗
C-reactive protein (CRP) is widely used in forensic science to identify inflammatory factors contributing to the cause of death. However, data on CRP changes in blood from cadavers that have decomposed in high-temperatur...
C-reactive protein (CRP) is widely used in forensic science to identify inflammatory factors contributing to the cause of death. However, data on CRP changes in blood from cadavers that have decomposed in high-temperature environments are limited, necessitating further research to enhance its forensic utility. This study aimed to investigate the changes in CRP levels in postmortem blood stored in high-temperature conditions to assess the validity and utility of CRP testing in decomposed cadavers. We analyzed changes in CRP levels in 106 autopsy blood samples from XXXX. Among these, 78 cases with elevated serum CRP levels (≥1 mg/dL) were used as the experimental group. Blood samples were stored at -80°C until thawed and analyzed for CRP changes over 0-30 d in a high-temperature (30°C-32°C) environment. Results showed that 78 cases (73.58%) had elevated serum CRP levels postmortem, while 58 cases (74.36%) had elevated CRP levels in thawed frozen whole blood (TFWB) at 0 d. Serum CRP levels decreased to 67.01% of antemortem serum CRP levels, while TFWB CRP levels at 0 d decreased to 42.85%. After adjusting for the average reduction rate, the number of cases with elevated TFWB CRP levels at 0 d increased to 68 (87.18%). No correlation was found between postmortem interval and TFWB CRP levels under high temperatures, supporting the stability and utility of TFWB CRP as a forensic marker for inflammatory conditions in decomposed cadavers. This study highlights the potential of using TFWB CRP levels for accurate postmortem analysis in forensic settings.
Interpol review of forensic firearm examination, 2022-2025.
Mattijssen EJAT, Kerkhoff W
Forensic Sci Int Synerg · 2026 Dec · PMID 42376276 · Full text
Abstract loading — click title to view on PubMed.
Legislative and forensic applications of melissopalynology, the study of pollen in honey.
Delport J, Villet MH
Forensic Sci Int Synerg · 2026 Dec · PMID 42376275 · Full text
Melissopalynology can provide scientific evidence about the authenticity of honey products, which is becoming a medical, economic and legal concern globally. Investigations can evaluate whether the pollen and spores (col...
Melissopalynology can provide scientific evidence about the authenticity of honey products, which is becoming a medical, economic and legal concern globally. Investigations can evaluate whether the pollen and spores (collectively termed palynomorphs) in a questioned honey sample are consistent with its purported geographical origin and botanical source(s). Legislation can therefore use such melissopalynological information to create benchmarks for authentic honey products and, by requiring explicit labelling of origins on honey products, can counteract honey fraud, protect consumers, and create premium economic products for small-scale honey production. If the authenticity of a honey product is challenged, melissopalynology must be able to provide a robust forensic service. This review evaluates how well melissopalynology qualifies as a forensic science that can be used to litigate under the legislation with which it is intimately associated. It meets criteria of scientific testability; professional peer review and publication; codified standard operating procedures for data collection, quantification and analysis; quantified error rates; and widespread acceptance within its scientific community, and it has been used in court cases. Its public databases are growing and proprietary databases need to be probatively auditable. Like other forensic sciences, melissopalynology is growing in technical sophistication but its ability to address specific relevant questions may depend on the contingencies of each case, e.g. the inadmissibility of illegally-obtained evidence. Melissopalynology is a science that satisfies the baselines of fitness for court, and this overview highlights areas where it can be refined so that its evidence is not merely admissible and legally defensible, but inherently robust forensic science.
Insights from the first synthetic cannabinoid clandestine lab dismantled in Brazil.
Meirelles GP, Gonçalves de Araújo KR, de Godoi AB … +4 more , Menezes MR, Neves LF, da Costa JL, Yonamine M
Forensic Sci Int · 2026 Jun · PMID 42372656 · Publisher ↗
The new psychoactive substance (NPS) situation in the world is a major challenge to toxicologists and supervisory bodies due to the constant evolution of the global drug market. According to the United Nations Office on...
The new psychoactive substance (NPS) situation in the world is a major challenge to toxicologists and supervisory bodies due to the constant evolution of the global drug market. According to the United Nations Office on Drugs and Crime, 1342 NPS have been identified, with synthetic cannabinoids accounting for 31.36% of these substances. While many substances appear and disappear rapidly, some NPS demonstrate prolonged market presence. For example, MDMB-4en-PINACA, first identified in 2017, has remained available to this day. In this context, the discovery of the first clandestine laboratory producing NPS in Brazil, specifically involving MDMB-4en-PINACA, served as a focal point for discussions on the accessibility of synthesis methods and the impact of legal restrictions and regulatory controls on the circulation of NPS. Furthermore, this article initiates a discussion on the potential role of artificial intelligence technologies in the synthesis of NPS.
Comparison of key diagnostics for probabilistic interpretation of STR mixture data generated with length-based and MPS methodologies.
Duke K, Cuenca D, Cheng K … +1 more , Wallin J
Forensic Sci Int Genet · 2026 Jun · PMID 42372428 · Publisher ↗
This study directly compared the mixture deconvolution performance of two probabilistic genotyping software applications: STRmix™ v2.8, which accepts length-based STR input data, and STRmix™ NGS v1.1.0, which accepts seq...
This study directly compared the mixture deconvolution performance of two probabilistic genotyping software applications: STRmix™ v2.8, which accepts length-based STR input data, and STRmix™ NGS v1.1.0, which accepts sequence-based STR input data. The same set of two-, three- and four-person DNA mixtures was used to generate data with the length-based GlobalFiler™ kit as well as the massively parallel sequencing (MPS) ForenSeq® Signature Prep and MainstAY kits, and the three resulting data sets were subsequently interpreted with the appropriate probabilistic genotyping software (PGS). The comparison of the software applications focused on three central interpretation diagnostics: likelihood ratio, mixture proportion, and genotype weight. Sequence-based likelihood ratios were on average 5 orders of magnitude higher than their length-based counterparts. Three possible factors that could account for this increase- assay sensitivity, isoallele detection, and isoallele population frequencies- were explored. To examine mixture proportions, template levels were considered, including bead normalization with MPS library preparation methods. The results of the comparisons of template levels, mixture components, and genotype weights indicate that STRmix™ v2.8 and STRmix™ NGS v1.1.0 have similar levels of deconvolution efficacy, meaning that the increased power of discrimination inherent in MPS data can be fully realized in a software-based approach to mixture interpretation without loss of genotyping accuracy. In addition, sequence information can provide invaluable assistance to experts in establishing the foundational user-defined assumptions under which these PGS systems operate. Overall, the study demonstrates that integrating MPS technologies with probabilistic genotyping offers a robust approach for enhancing STR mixture interpretation.
Determination of the new psychoactive substances MDMB-4en-PINACA, ADB-BUTINACA and some of their metabolites in blood and urine using DLLE-LC-MS/MS: application to real forensic case samples.
Çağılcı OC, Ocak ÜT, Ocak M … +1 more , Gümüşcü ZS
Forensic Sci Int · 2026 Jun · PMID 42364407 · Publisher ↗
MDMB-4en-PINACA and ADB-BUTINACA are indazole-derived synthetic cannabinoids that have increasingly been encountered in forensic toxicology, partly due to their potent cannabinoid receptor activity and their association...
MDMB-4en-PINACA and ADB-BUTINACA are indazole-derived synthetic cannabinoids that have increasingly been encountered in forensic toxicology, partly due to their potent cannabinoid receptor activity and their association with severe intoxication cases involving agitation, hallucinations, paranoia, and psychosis-like symptoms. In this study, a simplified and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method incorporating a simple and rapid sample preparation based on methanol-assisted protein precipitation followed by dispersive liquid-liquid extraction (DLLE) was developed and validated for the simultaneous determination of MDMB-4en-PINACA, ADB-BUTINACA, and their major metabolites, MDMB-4en-PINACA butanoic acid and ADB-BUTINACA N-butanoic acid, in blood and urine. The method provided effective separation and quantification of all analytes over a linear range of 1-100 ng/mL, with limits of detection between 0.51 and 1.20 ng/mL. No significant matrix interferences were observed, confirming adequate selectivity. The validated method was successfully applied to real forensic case samples, in which the inclusion of metabolite monitoring improved the confirmation of exposure particularly in cases where parent compounds were present at low concentrations or were no longer detectable. The results demonstrate that the proposed DLLE-LC-MS/MS method is a simple, robust, and reliable approach for the simultaneous determination of these synthetic cannabinoids and their metabolites in routine forensic toxicology, especially in investigations involving suspected synthetic cannabinoid-related neuropsychiatric manifestations such as acute psychosis.
The revolver halo as a forensic marker: Raman spectroscopic evidence of primer-driven gunshot residue deposition.
Solana-Aguilar EG, Vicente PG, Cano-Trujillo C … +5 more , Gil JLF, Jiménez JÁ, Uzquiano JFS, Montalvo G, García-Ruiz C
Forensic Sci Int · 2026 Jun · PMID 42361704 · Publisher ↗
The halo phenomenon in revolvers consists of a circular deposit of gunshot residues (GSR) formed around the fired chamber after firearm discharge. Despite its mention in forensic practice, its scientific basis and chemic...
The halo phenomenon in revolvers consists of a circular deposit of gunshot residues (GSR) formed around the fired chamber after firearm discharge. Despite its mention in forensic practice, its scientific basis and chemical origin have not been previously established. In this study, the occurrence, composition, and origin of revolver halos were investigated using Raman spectroscopy. Controlled firing experiments were conducted using four revolvers and four types of ammunition. Halos were observed in 15 out of 16 (94% of the shots), supporting their reliability as indicators for identifying the fired chamber. Raman analysis revealed that the halo is primarily composed of inorganic primer-derived compounds, including lead oxides and soot, demonstrating that the primer-rather than the propellant-is the main contributor to halo formation. Comparable spectral profiles were obtained for complete cartridges and primer-only firings, reinforcing the dominant role of primer residues. The results support the use of the revolver halo as a scientifically grounded tool in forensic firearm identification.
Research on the effects of signature size on experts' opinions.
Di̇ncer M, Canturk N, Dagalp R … +1 more , Seyhan E
Forensic Sci Int · 2026 Jun · PMID 42361703 · Publisher ↗
A signature is writing and/or signs that contain the signatory's personal characteristics and are used to indicate that people accept the authenticity of the formal and private transactions made by themselves in their da...
A signature is writing and/or signs that contain the signatory's personal characteristics and are used to indicate that people accept the authenticity of the formal and private transactions made by themselves in their daily lives and responsibilities arising from those transactions. If the documents are subject to forensic investigation and trial, forensic signature-examination experts are consulted to determine the identity of signatories. The experts reach an opinion at the end of their examinations and comparisons. But some issues affect the process of forming an accurate and reliable expert opinion about a questioned signature. In this study, the aim is to determine whether signatures differ across fields of different sizes and whether these changes affect examiners' opinions. Within the framework of the study, signature samples were collected using a signature form from a total of 60 volunteer participants who declared that they are healthy and who are at least high school graduates, between 19 and 65 years old, who are university and postgraduate students of the Institute of Forensic Sciences of Ankara University. The signatures in the smallest-sized boxes (2 ×0.5 cm) and the signatures on the larger-sized boxes, as well as the guidelines on the signature form, were compared and examined by the researcher according to 16 examination criteria using technical devices in a laboratory environment. In addition to the researcher, three handwriting and document examination experts examined the signatures on the signature forms. The data obtained from the study were analyzed using SPSS 20. The results show that signatures in the smallest areas exhibit significant changes in signature size, whereas criteria such as line quality, pen pressure, curls, and upward movements. Additionally, it was observed that the signature's size also influenced the experts' opinions. The Kruskal-Wallis test was used to assess whether the observed changes in participants' signatures and experts' views were associated with demographic variables, including gender, age group, and dominant hand. It was concluded that the initial movements of the signatures differed significantly according to the gender variable, and the pen pressure criterion differed significantly according to the dominant hand variable. However, no significant differences were observed in other criteria or expert opinions regarding the variables of gender, age group, and dominant hand.
Likelihood Ratios Given Activity-Level Propositions for DNA Transfer Evidence: Theoretical Foundations of the HaloGen Framework (Part I).
Gill P, Bleka Ø
Forensic Sci Int Genet · 2026 Jun · PMID 42350187 · Publisher ↗
The interpretation of trace DNA evidence at activity level requires explicit modelling of transfer, persistence, and the possibility that a relevant actor leaves no detectable DNA. We present the theoretical foundations...
The interpretation of trace DNA evidence at activity level requires explicit modelling of transfer, persistence, and the possibility that a relevant actor leaves no detectable DNA. We present the theoretical foundations of HaloGen, an open-source hierarchical Bayesian framework for evaluating DNA quantities under competing activity-level propositions. The propositions are framed in terms of alleged activities or actions; direct and secondary transfer are treated as transfer mechanisms through which those activities may give rise to the observed DNA. HaloGen accounts for zero transfer, multiple contributors, specified unknown contributors, unobserved actors, and multiple stains. Evidence is evaluated using an exhaustive-propositions likelihood-ratio framework that combines information across contributors and stains while propagating uncertainty in transfer and detection. Observed DNA quantities and non-detects are handled within a single probabilistic framework: detected quantities are evaluated using conditional-on-detection densities, whereas the probability that a relevant actor leaves no detectable DNA is represented by an empirically constrained fail-rate parameter. The framework yields transparent and stable behaviour: informative DNA quantities can support propositions involving direct transfer, while low-information or no-detect situations are neutral or defence-conservative. The empirical-clamped fail-rate policy prevents spurious inflation of likelihood ratios when non-detection of a relevant actor is plausible. This paper establishes the theoretical basis of HaloGen; a companion paper addresses validation and applied casework examples.
Likelihood Ratios Given Activity-Level Propositions for DNA Transfer Evidence: Practical Implementation and Simulation Studies Using the HaloGen Engine (Part II).
Gill P, Bleka Ø
Forensic Sci Int Genet · 2026 Jun · PMID 42350186 · Publisher ↗
The quantitative interpretation of low-template DNA findings given activity-level propositions requires models that can accommodate inter-laboratory variability, uncertainty in transfer and recovery, and case-specific as...
The quantitative interpretation of low-template DNA findings given activity-level propositions requires models that can accommodate inter-laboratory variability, uncertainty in transfer and recovery, and case-specific assumptions. This paper presents the practical implementation of HaloGen, an open-source hierarchical Bayesian framework for calculating activity-level likelihood ratios (LRs) from DNA quantity data. We compare three modelling approaches derived from the framework: a Group model, which combines data across laboratories, a hierarchically informed Lab-Bayes model, and a standalone, laboratory specific Lab-Vague model. Through simulation studies, we show that evidential strength is sensitive not only to DNA quantity but also to case context, particularly the assumed number of relevant actors (N), the treatment of specified unknown contributors, and the choice of laboratory calibration. Inter-laboratory differences in DNA recovery and non-detection can lead to materially different LRs when these data are used within the HaloGen framework, so pooled or external data should not be used uncritically. To address practical implementation, we propose a minimum-effort calibration pathway for laboratories wishing to use HaloGen for quantitative activity-level LR reporting. The results indicate that a limited number of local direct/secondary transfer experiments can improve relevance compared with exclusive reliance on a pooled population model, although the adequacy of any dataset remains case- and proposition-dependent. The findings clarify how contextual assumptions enter mathematically into activity-level inference and underscore the importance of transparent specification of propositions, data relevance, model assumptions, and remaining expert judgement.
Forensic evaluation of 101 identity-informative SNPs in a Filipino population using massively parallel sequencing.
Salvador JM, Apaga DLT, Sosing MV … +7 more , Estrella CS, Lazo MLPN, Rodriguez JJRB, Dennis SME, Calacal GC, Matias AMA, De Ungria MCA
Forensic Sci Int Genet · 2026 Jun · PMID 42349326 · Publisher ↗
DNA-based human identification traditionally relies on short tandem repeats (STRs) as the primary genetic markers for analysis. However, single nucleotide polymorphisms (SNPs), particularly identity-informative SNPs (iiS...
DNA-based human identification traditionally relies on short tandem repeats (STRs) as the primary genetic markers for analysis. However, single nucleotide polymorphisms (SNPs), particularly identity-informative SNPs (iiSNPs) located on autosomes, offer distinct advantages for analyzing degraded DNA because of their low mutation rates and short amplicon lengths. Massively parallel sequencing (MPS) has enhanced forensic capabilities by enabling the simultaneous analysis of large numbers of STRs and SNPs in a single assay. This study characterized 101 iiSNPs in a representative Filipino population using two commercially available MPS kits (Precision ID and ForenSeq™ DNA Signature Prep Kits), contributing data from an underrepresented Southeast Asian population to forensic DNA databases. Genotype data from 143 unrelated Filipino males from the National Capital Region (NCR) and surrounding areas were analyzed to estimate allele frequencies, forensic efficiency parameters, Hardy-Weinberg equilibrium (HWE), linkage disequilibrium (LD), population structure, and kinship performance for robust statistical interpretation in casework. All markers conformed to HWE expectations after correction, and no significant LD was detected among iiSNPs or between iiSNPs and 23 autosomal STRs (aSTRs) previously generated using the PowerPlex® 21 System and Verifiler™ Direct PCR Amplification Kit. This supports the assumption of marker independence and the application of standard forensic statistical models. Of the 101 iiSNPs evaluated, 64 met the criteria for broad forensic applicability. Both iiSNP panels demonstrated strong individualization power, with combined match probabilities five- to six-fold lower than those of 23 aSTRs. Population genetic analyses indicated that Filipinos cluster closely with East Asian populations relative to the other populations included in the analyses, while exhibiting distinct genetic characteristics. This underscores the importance of population-specific reference data. Furthermore, simulated kinship analyses showed that iiSNPs performed comparably to aSTRs for first-degree relationships and provided added value when combined with aSTRs for second-degree relationships. In contrast, neither the iiSNP-only, aSTR-only, nor the combined aSTR-iiSNP marker systems were sufficient to reliably resolve third-degree relationships, highlighting the need for higher-density iiSNP panels. This study established the first Filipino forensic iiSNP database and validated the forensic applicability of 101 iiSNPs included in two commercial MPS panels. Future studies should extend the analysis to other Philippine population groups, including Indigenous cultural communities (ICCs) and Indigenous peoples (IPs), which remain culturally and geographically distinct from mainstream populations. Additionally, refining universal iiSNP panels and exploring higher-density MPS datasets may help identify new markers to further strengthen forensic DNA profiling in criminal investigations in the Philippines.
Reprocessing of hair roots using conventional forensic DNA analysis following RapidHIT® ID processing.
Haines A, Aljumaili T, Bruce D
Forensic Sci Int Genet · 2026 Jun · PMID 42349325 · Publisher ↗
Hair traces are frequently recovered at crime scenes and represent a valuable source of forensic DNA, although the cellular content of hair roots varies substantially depending on growth stage, with shed hairs typically...
Hair traces are frequently recovered at crime scenes and represent a valuable source of forensic DNA, although the cellular content of hair roots varies substantially depending on growth stage, with shed hairs typically containing limited DNA. Rapid DNA platforms such as the RapidHIT® ID (RHID) system enable expedited STR profiling; however, the impact of RHID processing on downstream laboratory-based analyses remains an important consideration. In this study, the ability to reprocess hair roots following RHID analysis was evaluated, and Diamond™ Nucleic Acid Dye (DD) was employed to assess cellular retention and degradation associated with the RHID workflow. Hair roots representing a range of nuclei counts were initially assessed using DD staining and fluorescence microscopy, processed using the RHID system, and subsequently recovered from the cartridge for conventional forensic DNA analysis. Post‑RHID assessment using DD enabled visualisation of remaining cellular material and provided an indication of substrate integrity following rapid DNA processing. Recovered hair roots were subjected to standard lysis, extraction, and STR amplification protocols to determine the feasibility of downstream profiling. Results demonstrated that hair roots, particularly those with higher initial nuclei counts, could be successfully reprocessed following RHID analysis, yielding DNA profiles suitable for comparison and further forensic applications. DD staining indicated that cellular material was retained post‑RHID, supporting the suitability of recovered hair roots for additional testing. In contrast, shed hairs were less likely to yield usable profiles after reprocessing, reflecting their inherently limited cellular content rather than RHID‑induced degradation. These findings demonstrate that RHID processing does not preclude subsequent laboratory analysis of hair roots and highlight the value of hair root visualisation prior to processing, as demonstrated here using Diamond™ Dye (DD). Collectively, this approach supports the use of rapid DNA workflows while preserving evidentiary material for confirmatory and extended forensic analyses.
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