Journal of forensic sciences最新文献

Scene investigation, a fundamental component of medicolegal death investigation, has not been adequately studied. Using data from an electronic case management system, we analyzed 4509 deaths from two nationally accredited offices, over a 4-year period (2018–2021). We determined the proportion of death scenes directly investigated by medicolegal death investigators (MDIs) and examined factors associated with direct scene investigation. MDIs directly investigated scenes in 76% of the cases in this study, which excluded deaths occurring in medical facilities. Using logistic regression to control for the effects of all variables analyzed, we explored factors that were positively and negatively associated with direct scene investigation. MDIs were most likely to examine scenes when the decedents were young, male, white, the death occurred outdoors, and the circumstances were reported as apparent homicide, suicide, or otherwise “suspicious.” Scenes were less likely to be directly investigated by MDIs if the death was reported in the hours after midnight and originally reported as “natural.” Scene responses differed between the two offices in the study. Overall, these results indicate a need to further explore potential barriers or biases that may impact the consistency and accuracy of medicolegal death investigation. The findings also suggest a need to study operational guidelines or structural constraints that shape individual office practices. This study adds to limited research in the field and contributes information to support development of a more consistent, rigorous national response to this critical public health and public safety function.

Contemporary research has demonstrated the effects of bias on, even expert, forensic decision making. The paper aimed to test if forensically relevant face recognition decisions could be influenced by biasing information. A 3 (Bias (within-subjects): positive bias vs. negative bias vs. control) × 2 (evidence strength (between-subjects): weak video evidence (N = 97) vs. strong video evidence (N = 98)) × 2 (target presence (within-subjects): absent vs. present) mixed-design was utilized. Confidence, accuracy, and decision time were measured. In total, 195 participants were recruited. The Cambridge face memory test+ was used to measure face recognition ability. Participants saw 36 videos emulating Closed Circuit Television (CCTV) footage of a person walking down the corridor. Participants were randomly allocated to either the strong or weak evidence condition. Participants were shown a statement for each video that contained either a positive bias (target face matched the face in the video), a negative bias (target face did not match the face in the video), or control (no statement provided). Participants were then presented with a target face and asked if it matched the face seen in the previous video. There was a significant interaction between the bias and the target presence factors, with accuracy and confidence increasing and decision times decreasing when a positive bias statement was used when the target was present. Face recognition abilities did not act as a covariate. Bias may influence facial recognition decisions, and superior face recognition abilities do not undermine the influence of bias. Recommendations/implications, such as linear sequential unmasking, were discussed.

Forensic staff play a crucial role in law enforcement through providing specialist services to police agencies in criminal investigations. Given the unique work, including frequent exposure to potentially distressing material, administrative workloads, and other work-related pressures, forensic staff are at risk of increased occupational stress. The current study examined the demands and resources associated with stress-related outcomes among forensic staff. It further provides descriptions of the coping strategies used, perceptions of organizational support resources, and attitudes toward help-seeking and using sick leave. Participants were 114 sworn and non-sworn forensic staff working in an Australian law enforcement organization. The study used a mixed methods design with participants completing survey questions online. Quantitative data were analyzed using bivariate correlations and partial least squares regression analyses. Qualitative data were analyzed using thematic analysis. Results identified the key role of occupational and organizational stressors, and forensic-specific job-related demands, in predicting various stress-related outcomes. Supervisor support, peer support, and psychosocial safety climate also had a key role in predicting stress-related outcomes among forensic staff. Law enforcement organizations employing staff in forensic job roles should take a holistic approach to optimizing demands which not only focuses on trauma, but also on mitigating occupational and organizational stressors. Demands specific to the role of forensics also need to be considered. In an effort to offset job demands, police agencies should seek to uplift the capacity of key resources such as supervisors and peers and should focus on ensuring a positive psychosocial safety climate.

Blowflies are important to estimate the postmortem interval (PMI), since they are the first to interact with the carcass. However, depending on the decomposition stage, only pupae can be found. A method that has currently been suggested is the use of cuticular hydrocarbons (CHCs) in forensically important fly species to aid in estimating PMI; however, studies from the pupal stage are rare. Therefore, this study aimed to test two hypotheses: (1) CHCs from fly pupae can be used as an auxiliary taxonomic tool. (2) There is significant chronological variation in composition throughout pupal development. 315 pupae were used from two fly species of different ages, being 21 pupae for each age group and using three pupae per extraction, n = 7, from which the CHCs were extracted every hour, from the first hour to the tenth; then, samples were collected every 24 h until adult emergence. We found that in the cuticle of Chrysomya albiceps and Chrysomya megacephala, pupae detected 19 and 23 compounds, respectively, identified as linear alkanes, branched alkanes, and alkenes. According to the results, CHCs of the pupae vary significantly between the species and throughout their development, with compounds that are specific to the initial hours and others to the final hours. We can conclude that our results are promising for use in forensics, as changes in intra-pupal development result in a characteristic chemical profile throughout the ages analyzed, therefore helping criminal experts in estimating the PMI.

In routine forensic chemical casework where measurements are performed on reference materials, determination of measurement uncertainty is described in several guidelines. The proposed methods often have the drawback that they are not derived from a statistical framework and may lead to conservative confidence intervals. Furthermore, the formulas involved may vary considerably for different types of reference material. The current study presents a method for determination of measurement uncertainty that is both statistically sound and uniform for different types of reference material, namely material from proficiency tests, certified reference material, and noncertified reference material. The statistical model used for measurements uses relative standard deviations. The method is based on analysis of two sources of uncertainty, namely the random variation in the measurement itself and uncertainty connected to the bias of the process. It is explained how the method works when there is bias correction of results. It is also described how the method works if no correction is applied. Furthermore, the results are compared using simulation experiments, showing a better performance of the proposed method when compared with commonly used alternatives.

Anti-forensics refers to techniques designed to obstruct the discovery of evidence in digital forensic investigations. File-wiping is one of the anti-forensic techniques that make data recovery impossible by overwriting data with specific patterns. This technique poses significant challenges to investigators. Our study evaluates the effectiveness of file-wiping applications on the Android OS from the anti-forensic perspective. We selected six applications from the Google Play Store that support file-level wiping. By analyzing these applications using reverse engineering and digital forensic tools, we addressed the three key research questions. First, we discovered that although one application claimed to provide file-wiping functionality, it actually performed simple file deletions, making the deleted files recoverable. Second, we found that file-wiping applications did not adhere to file-wiping standards or guidelines. Lastly, by examining artifacts generated by the Android OS and applications during the file-wiping process, we were able to reveal evidence of tool execution and artifacts of wiped files. Based on these findings, we propose a novel evaluation framework that assists digital forensic investigators in detecting traces of wiping activity and inferring information about deleted data on Android devices.

Adhesive tapes are often a subject of forensic examinations as they are frequently encountered in a variety of cases involving drugs of abuse, bombings, homicides, kidnappings, robberies, or sexual assaults. The analytical characterization of such adhesive tape evidence can be useful for assessing potential contact between the suspect, the victim, and/or the crime scene. However, adhesive tapes frequently serve as substrates for fingermarks, and the examination of these impressions takes precedence over the characterization of the tape due to the higher evidentiary value associated with fingermarks. This study evaluated the efficacy of commonly available fingermark development methods for fingermarks on adhesive tapes and investigated their effects on the characterization of the adhesive tapes using ATR-FTIR spectroscopy. Gentian violet and iodine fuming were able to develop fingermarks on various types of tapes with good ridge detail clarity and good contrast. These techniques were also compatible with the characterization of the tapes using ATR-FTIR spectroscopy. Iodine fuming did not introduce any additional peaks in the ATR-FTIR spectra. Gentian violet presented a few minor additional peaks at 1644, 1586, and 963 cm⁻¹. An additional preliminary study on the effect of selected fingermark techniques on chemometric prediction of adhesive tapes was conducted. The results showed that iodine fuming resulted in more prediction accuracy compared to gentian violet. The findings of this study will contribute to determining the strategic choice for the fingermark development on adhesive tapes as well as its subsequent characterization and also strengthen the interpretation of adhesive tape evidence using chemometrics.

Short tandem repeat (STR) analysis is the cornerstone of forensic human identification due to its high discriminatory power and robustness. A concordance study was conducted to evaluate allele call consistency between two STR multiplex kits: PowerPlex® ESI 16 Fast (Promega Corporation, Madison, WI, USA) and Investigator®24plex GO! Kit (QIAGEN GmbH, Hilden, Germany). A total of 2000 buccal FTA cards (Whatman™ Flinders Technology Associates, Cytiva, Marlborough, MA, USA) samples previously typed with the PowerPlex® ESI 16 Fast Kit were re-analyzed using the Investigator® 24plex GO! Kit. An overall concordance rate of 99.982% was observed (59,989 concordant allele calls out of 60,000 total calls). Eleven discordant alleles were identified, including five cases of allelic dropout at distinct loci, five instances of allele shift (typically between D1S1656 and the adjacent DYS391), and one true mismatch at D1S1656. All discordances were confirmed by repeated amplification using both the PowerPlex® ESI 16 Fast and Investigator® 24plex GO! Kits, as well as the Investigator® 24plex QS Kit (QIAGEN GmbH, Hilden, Germany). The mismatch at D1S1656 was further confirmed by sequencing. The low discordance rate supports the reliability of the Investigator® 24plex GO! Kit for forensic reference databasing and enables a confident transition from the PowerPlex® ESI 16 Fast Kit.

Lipstick traces can be recovered from the crime scene on various substrates and linked to the lipstick worn by the suspect or victim. These samples are usually collected using the swabbing method from the lips. Sometimes, the same samples are stored in forensic laboratories for years due to a backlog of cases, which affects the samples' originality. Therefore, in this study, a comprehensive study of the wearing and storage effects was conducted to assess the period up to which lipstick traces can be linked to their source by analyzing 20 brands of red lipsticks using ATR-FTIR spectroscopy and chemometric tools. The study was divided into two phases. In Phase I, samples were collected using the swabbing method from the lips of volunteers after 5 min, 1, 3, and 5 h of application, followed by ATR-FTIR spectroscopic analysis. Similarly, in Phase II, the same swabs were kept for 1 year to investigate their aging process, followed by ATR-FTIR spectroscopic analysis. The results showed that all the pristine samples can be discriminated with 100% LDA accuracy. The built training model was also validated, which showed 95% accuracy. Chemometric prediction of the worn samples yielded 80% accuracy for Phase I. However, a reduced accuracy (45%) was observed for Phase II due to the drying effect and loss of sample over time. It can be concluded that these types of samples must not be stored for a longer duration in real-case scenarios, so that the authenticity of the evidence is retained.

Miranda v. Arizona (1966) protects waivers in police custody from potential self-incrimination unless the waiver decision was knowingly and intelligently effectuated. Despite extensive research on Miranda comprehension, very little is known about these crucial waiver decisions. This study explores new ground for formerly incarcerated persons (FIPs) and their capacity for knowing and intelligent waivers. In a Prolific investigation, 182 FIPs were recruited, with most having multiple arrests and subsequent incarcerations. They were tested on the Standardized Assessment of Miranda Abilities (SAMA), the best validated measure of Miranda abilities for adult detainees. Results of a linear discriminant analysis indicated that the Miranda-proficient reasoning group was predicted by strong Miranda-relevant vocabulary and low scores on the Trust in Law Enforcement (TLE) subscale. Contrastingly, the Miranda-compromised group demonstrated significantly less advanced Miranda vocabulary with concomitantly high TLE scores. Despite criminal backgrounds, TLE overrode other considerations for Miranda waivers. Based on a qualitative analysis, Miranda-compromised FIPs seriously overestimated their own abilities to handle police questioning, whereas Miranda-proficient FIPs appeared more skeptical of any advantages of waiving silence/counsel. In conclusion, this Miranda-compromised group held seemingly more trusting views of arresting officers and saw more benefits to waive their rights than their Miranda-proficient counterparts.