Forensic science international最新文献

During routine casework, fingerprint examiners are required to make decisions pertaining to the sufficiency of friction ridge skin impressions. Prior experimental research has established that differences of opinion between examiners are expected, though it is uncertain if these findings are representative of the decisions made during casework. In this study, 5000 job-cards completed by fingerprint experts of the NSW Police Force were scrutinised to track the differences of opinion that occurred between examiners. Experts recorded 19,491 casework decisions, which resulted in 8964 reported identification and inconclusive determinations. Expert decision making was found to be unanimous in 94.8 % of these determinations; 4.6 % involved one expert-to-expert disagreement; and 0.5 % involved two expert-to-expert disagreements. Nil determinations featured more than two expert-to-expert disagreements. Expert-to-expert disagreements occurred in 3.7 % of all identification and inconclusive casework verification decisions. However, verifying experts were more likely to agree with a prior expert’s identification decision, than a prior expert’s inconclusive decision. The observed expert-to-expert identification disagreement rate was 2.0 %, whereas the observed expert-to-expert inconclusive disagreement rate was 12.5 %. Overall, most casework disagreements arose due to subjective differences concerning the suitability of friction ridge skin information for comparison or sufficiency for identification. Experts were more concordant in their decision-making with other experts than with trainees, and approximately three times more likely to disagree with a prior trainees’ identification or inconclusive decision than a prior experts’ identification or inconclusive decision. We assume these differences reflect trainees’ developing proficiencies in assessing the suitability or sufficiency of friction ridge skin impression information. Differences of opinion in casework are expected, which exposes the subjective nature of fingerprint decision-making. Computer-based quality metric and likelihood ratio tools should be considered for use in casework to guide examiner evaluations and mitigate examiner disagreements.

Latent fingerprints (LFPs) are predominantly used for personal identification, but in recent years research has shown their potential for drug screening. Despite this there is no standardised collection method to allow accurate drug test interpretation. We sought to help address this by characterising different variables related to sweat deposition in LFPs as the knowledge is limited. A series of experiments were conducted firstly to validate a novel tool called the Ridgeway (Intelligent Fingerprint Ltd. UK) to quantify the amount of sweat deposited from a LFP using the refractive index (RI). A significant positive correlation was observed between the Ridgeway score (Rs) and LFP mass [r = 0.868, p < 0.01]. The Rs was used as means to investigate optimal sampling to characterise sample deposition for drug screening purposes. It was found with a consistent disposition pressure (300 – 400 g) and surface (glass slide) no significant difference was observed between the left and right index finger [left: p = 0.938; right: p = 0.838]. Significantly higher Rs [p<0.01] were obtained when 10 cumulative LFPs were deposited compared to a single LFP, suggesting a larger sweat quantity. We also wanted to investigate optimal eccrine sweat sampling to confirm drug ingestion over drug contamination of the fingerprint. We found that wearing gloves did not significantly improve mean difference in Rs when compared to no gloves [p = 0.239]. To produce eccrine only LFPs, external contamination (e.g. sebaceous sweat) needs to be removed. Soap with lint free tissue was significantly better for this compared to antibacterial hand gel [p<0.01]. Our findings showed that the Ridgeway tool effectively quantified LFPs at the point of deposition using a refractive index and enabled us to establish conditions for consistent LFP sampling.

Species categorical authentication of accelerants has traditionally relied on fire debris analysis. To explore a novel method for identifying the accelerants species, four commonly used accelerants for arson were loaded onto different substrates and ignited at different locations. The entire combustion process was recorded and flame characteristics were analyzed. The results showed that the probability density function (PDF) of flame apex angle counts within a certain period after ignition can be used to distinguish accelerant species, and this method is not affected by accelerant loading amount, ignition location, and substrate, demonstrating strong stability and universality, while the temporal variation of flame area and the value obtained by dividing half of the flame width by the flame height (tangent of flame cone angle) can effectively differentiate gasoline and diesel. The utilization of flame characteristics for identifying accelerants species holds significant implications for arson investigation.

Etomidate as a non-barbiturate sedative, has central inhibitory effect and addiction and has been listed as a controlled drug in some countries due to the abusing trend nowadays. Therefore, rapid and sensitive detection of etomidate is of great significance. In this work, a novel fluorescent sensing probe (CuNCs@MIPs) based on copper nanoclusters (CuNCs) and molecular imprinted polymers (MIPs) has been firstly reported. CuNCs was environment-friendly synthesized using poly(vinylpyrrolidone) as a template and ascorbic acid as a reducing agent. After functionalized with molecular imprinting technique, the CuNCs@MIPs probe has special binding cavities on surface to target etomidate, causing the fluorescence intensity rapidly decrease, which confirmed it has excellent sensitivity, selectivity and stability. Under optimal conditions, the fluorescent sensing probe presented high precision linear relationship for etomidate in range of 10–500 ng/ml with detection limit of 10 ng/ml, and the whole detection process was completed within 10 min. This sensing method has also been applied to real samples detection, still demonstrated excellent feasibility in electronic cigarette liquids and urine. More importantly, compared with previous methods, this fluorescent sensing method has advantages such as rapid, simple and easy to operate. Collectively, the proposed CuNCs@MIPs sensing probe has good fluorescence characteristics and simple synthesis strategy, showed a great potential in etomidate detection and application.

Wastewater based epidemiology (WBE) has been used worldwide to estimate drug consumption routinely. Even though WBE provides valuable data to support legal and health interventions associated to drug use, monitoring studies in Portuguese wastewaters are scarce. Hence, this work aimed to estimate the consumption of some conventional abuse and illicit drugs such as amphetamine (AMP), methamphetamine (MAMP), 3,4-methylenedioxymethamphetamine (MDMA), and the synthetic cathinones buphedrone (BPD), butylone (BTL), 3,4-dimethylmethcathinone (3,4-DMMC) and 3-methylmethcathinone (3-MMC), considering not only the liquid phase, but also the suspended particulate matter (SPM). Moreover, the enantiomeric profiling of the samples was studied, exploring for the first time the possible enantioselective sorption of these drugs onto SPM. For that, 24 h composite raw wastewaters were collected from a conventional wastewater treatment plant (WWTP) in Portugal. After extraction, the liquid phase and SPM extracts were derivatized with an enantiomerically pure reagent and then, analysed using a gas chromatography-mass spectrometry (GC-MS) analytical method. The results showed a low and non-enantioselective adsorption to SPM at environmental relevant levels. Only (S)-AMP was detected in two SPM samples, whereas AMP, MAMP, MDMA, BPD, and 3,4-DMMC were detected in the liquid phase. AMP was the most frequently found drug with an estimated load up to 166.0 mg day⁻¹ 1000 people⁻¹ and mostly found with enrichment of (S)-AMP. Nevertheless, (R)-AMP was also determined, which may be related to the consumption of either the illicit racemic AMP or the medicine (R)-deprenyl. The use of MDMA, MAMP and synthetic cathinones (BPD and 3,4-DMMC) was also suggested in Portugal. Nevertheless, the levels and the consumption estimate of the target chemicals were lower than in other European countries or worldwide. These findings provide the first step to the implementation of WBE monitoring campaigns to assess the status of drug consumption in Portuguese communities, contributing to the understanding of drug use patterns and trends worldwide and helping enforce preventive measures.

The chemical recovery of a defaced serial number is a common forensic science practice, however it is not understood how proficient experts perform in correctly identifying recovered serial numbers. Understanding the accuracy of experts and how they compare to novices in character recognition can help to establish a baseline for this expertise. In this study an expert-novice comparison assessment was completed involving 118 test plates, each stamped with six randomised alphanumeric characters. The plates were defaced and chemically recovered before being viewed by multiple participants over six time intervals. A total of 3169 character inspections were completed. An assessment of confidence and error rates were calculated for both expert (trained) and novice (untrained) participants. Errors were counted when a participant interpreted a different character to that of the ground truth and believed the result was accurate for reporting. The results showed a similar (2.3 % and 2.4 %) error rate for the cohorts, however a statistical difference in confidence levels was recorded, demonstrating the more conservative nature of experts. This study aims to assist in validating practitioner interpretations, through addressing some forensic science criticisms, such as establishing error rates to routine scientific practices.

Loperamide, a potent μ-opioid receptor agonist used as an antidiarrheal drug, exhibits increased bioavailability at supratherapeutic doses, causing potential central nervous system effects. Its misuse for opioid withdrawal relief and euphoria can lead to dangerously elevated blood levels, causing severe cardiac dysrhythmias and death. This study aimed to compare loperamide positive autopsy cases in Sweden and Finland after the introduction of postmortem toxicological analysis of loperamide, focusing on loperamide’s role in fatalities and identifying common characteristics among those affected. All cases with detected loperamide in femoral blood at forensic autopsies in Sweden (2012–2022) and Finland (2017–2022) were included. In Sweden, loperamide was detected in 126 individuals, and in Finland, in 111 individuals. The incidence of individuals positive for loperamide in postmortem femoral blood increased steadily over the study duration in both Sweden and Finland. Loperamide related fatalities were observed exclusively in Sweden (n=80), predominantly involving younger males with histories of substance abuse, typically classified as accidental deaths. The group of loperamide nonrelated deaths in Sweden mirrored the entirety of cases in Finland. The concentration of loperamide in postmortem femoral blood was significantly higher in cases where loperamide was considered the cause of death (median 0.140 μg/g) compared to cases where loperamide contributed (median 0.080 μg/g), as well as in deaths unrelated to loperamide in both countries (Sweden: median 0.029 μg/g; Finland: median 0.010 μg/ml). The high limit of quantification for loperamide in Sweden may underestimate therapeutic users in epidemiological assessments. This study underscores the absence of loperamide misuse in Finland and indicates a rising trend of loperamide abuse in Sweden.

Purpose

To summarize recent cases of fatal insulin poisoning both domestically and internationally, thereby offering valuable insights for the forensic identification of insulin overdose cases.

Methods

Literature published since 2000 on fatal insulin overdose were systematically searched and screened. Data encompassing variables such as year, age, sex, cause of death, scene conditions, occupations, medical histories of victims and perpetrators, autopsy timing, dosage and administration methods, forensic pathology, and toxicological analysis, were compiled for rigorous statistical analysis.

Results

Among the 29 fatal cases of insulin poisoning, suicides and homicides accounted for 55.2 % and 41.4 %, respectively. Precisely 34.5 % of victims or perpetrators were associated with the medical industry, 27.6 % had diabetes, and 24.1 % had mental illnesses such as depression. Intravenous injection resulted in quicker death than did subcutaneous injection. In some cases, immunohistochemical staining of insulin and protamine at injection sites yielded positive results. The average molar ratio of insulin to C-peptide in post-mortem blood was 13.76 ± 5.167, indicating a significant diagnostic value for insulin poisoning.

Conclusion

Assessment of cases of fatal insulin overdose should be thorough, incorporating case investigation, scene examination, medical records review, autopsy findings, pathological examinations, and laboratory tests, alongside considering the condition of the body and timing of death autopsy. Using mass spectrometry to detect insulin proves valuable, particularly in cases of poor body preservation.

Sudden unexplained death (SUD) is not uncommon in forensic pathology. Yet, diagnosis of SUD remains challenging due to lack of specific biomarkers. This study aimed to screen differentially expressed proteins (DEPs) and validate their usefulness as diagnostic biomarkers for SUD cases. We designed a three-phase investigation, where in the discovery phase, formalin-fixed paraffin-embedded (FFPE) heart specimens were screened through label-free proteomic analysis of cases dying from SUD, mechanical injury and carbon monoxide (CO) intoxication. A total of 26 proteins were identified to be DEPs for the SUD cases after rigorous criterion. Bioinformatics and Adaboost-recursive feature elimination (RFE) analysis further revealed that three of the 26 proteins (MYH6, COX5B and TNNT2) were potential discriminative biomarkers. In the training phase, MYH6 and COX5B were verified to be true DEPs in cardiac tissues from 29 independent SUD cases as compared with a serial of control cases (n = 42). Receiver operating characteristic (ROC) analysis illustrated that combination of MYH6 and COX5B achieved optimal diagnostic sensitivity (89.7 %) and specificity (84.4 %), with area under the curve (AUC) being 0.91. A diagnostic software based on the logistic regression formula derived from the training phase was then constructed. In the validation phase, the diagnostic software was applied to eight authentic SUD cases, seven (87.5 %) of which were accurately recognized. Our study provides a valid strategy towards practical diagnosis of SUD by integrating cardiac MYH6 and COX5B as dual diagnostic biomarkers.