Distribution of the Minutiae in Hypothenar Palm Prints in Slovak Adults: Indications for Personal Identification

Minutiae are small distinguishing features found along every ridge flow, which make each friction ridge print unique. The most common friction ridge prints found at the crime scene are fingerprints; therefore, the most of the minutiae studies are focused exactly on this kind of prints. The authors believe that further examination and enlargement of the palm print database could result in better use of the palm prints for personal identification. We analyzed a total of 160 palm prints from 40 females and 40 males aged between 18 and 70 years from Slovakia. For the evaluation of the minutiae, the area of the hypothenar had to be marked out. The classification of the minutiae used for this study was based on a modified version of the classification system using the total of 13 types of minutiae. The frequency of every minutiae type was calculated and, using the chi-square test with Yates's correction, bilateral and sex differences were assessed. The relationship between the different types of minutiae was examined with Pearson's correlation test. During the initial phases of the identification process, the focus should be on the least common types of minutiae (Y or M and return), which were found not to correlate; thus, their mutual occurrence is random (e.g., overlap—Y or M, crossbar—return, or Y or M—dock). The results of the present study show which specific minutiae types are the most suitable for personal identification. These findings may be beneficial in more effective outcome of the identification process.     

Composite Machine Learning Algorithm for Material Sourcing,

This study developed a composite machine learning algorithm for attribution of materials of forensic interest (like ammonium nitrate) to original sources. k-nearest neighbor and random forest models were used for source elimination and classification, respectively, in a two-step, composite algorithm based on particle color, size/shape, and trace element concentration features. Novel approaches for simulation to supplement within-source reference features based on empirically measured multi-lot analyses, an improved hold-one-lot-out method for cross-validation, an assessment of the likelihood of the presence of a reference sample, fusion of the source probabilities from the respective classification models, and the calculation of metrics for assessing ensemble sourcing performance are described. Excellent sourcing predictions were obtained; the sourcing algorithm identified the correct source as the top choice 89% of the time, and the correct source was identified to be an average of 2.7 times more likely than the most likely incorrect source.     

Two-dimensional metric comparisons between dynamic bare footprints and insole foot impressions-forensic implications

Footwear may be found at crime scenes as physical evidence. Such footwear often has impression features of the wearer’s foot on the insole of the shoe. Scientific research and literature have established that footprints are distinct. This study compares two-dimensional measurements on bare footprints to foot impressions on insoles to determine if significant differences or similarities exist. Dynamic footprints were collected from 51 donors using the Identicator® Inkless Shoe Print Model LE 25P system. Seven foot length and width measurements were taken based on the Reel linear measurement method. Footprint measurements between bare footprints and foot impressions on the insoles were compared. Only two differences (p > 0.05) were observed between the various bare footprint and insole foot impression measurements on the right and left side for most of the measurements, CALC (p < 0.001) and A1 (p = 0.04). Bare footprint and insole A5 measurements on the left side were also significantly different (p = 0.015). The results of the study have implications in the forensic analysis of foot impression evidence on insoles in footwear in assisting with identifying the wearer of said footwear. Situations may arise in the forensic context when comparing the foot impression on the insole of footwear to a suspect’s bare footprint or a footprint from post-mortem remains. This study contributes to the scant literature available on the topic and to understanding the similarities and differences observed in the various linear measurements that may be utilized in the comparison process of footprint impressions on shoe insoles to bare footprints.     

How to share and utilise expertise in a police forensic department through externalisation and mutualisation

The technique of fire investigation is a forensic domain in which expertise and analogies play a central role. To learn how fire investigators use these analogies to support their work, we conducted an ethnographic study in a Swiss forensic police department. To propose a suitable knowledge-management strategy, we also evaluated the knowledge conservation and sharing within the department. Our results highlighted that actionable knowledge is registered mainly in the investigators’ memories of a few, very experienced, individuals. Without experience with fire-incident investigations, an agent generally requires help from a more experienced colleague, who will then use his memory to find a similar case, which can contribute to the solution of the ongoing one. The research also established that knowledge is exchanged orally during on-site investigations and that knowledge receivers are generally those who are present on the scene. Using these findings, we suggest building a case library to support the externalisation and sharing of knowledge.     

Prevalence of organic gunshot residues in police vehicles

The present study investigated the organic gunshot residue (OGSR) background level of police vehicles in Switzerland. Specimens from 64 vehicles belonging to two regional police services were collected and analysed by LC-MS in positive mode. The driver’s and back seats were sampled separately to monitor potential differences between locations and to assess the risks of a suspect being contaminated by OGSR during transportation to a police station.The results showed that most of the 64 vehicles were uncontaminated (44 driver’s seats and 38 back seats respectively). Up to six of the seven targeted compounds were detected in a single sample, once on a driver’s seat and twice on back seats. The contamination frequency generally decreased as the number of compounds detected together increased. The amounts detected were in the low ng range and less than amounts generally detected just after discharge on a shooter. Our data indicated that detecting a combination of four or more compounds on a police vehicle seat appears to be a relatively rare occurrence. The background contamination observed was most probably due to secondary transfer from police officers (e.g. through recent participation in a shooting session or firearm manipulation) or from firearms stored in the vehicles. The present results might be used as a recommendation to minimize contact of a suspect with contaminated surfaces if OGSR is implemented in routine work in parallel to IGSR analysis.     

对证据调查变革的认识

仔细分析证据调查不同阶段的原因和特点,不但可以对今后证据调查的发展方向有所了解,而且可以把握证据调查的内在规律,预测证据调查的发展趋势,给我们选择和运用证据调查的方法、手段带来很大的便利。     

秘密侦查性质的多维解读

传统上我国学术界普遍从手段或措施的角度对秘密侦查予以认识。这种认识缺陷导致人们对秘密侦查“神秘化”,秘密侦查法治化状况极差。从诉讼法理上而言,秘密侦查的性质应为一种侦查行为和诉讼行为,它具有自身的特征,与强制侦查行为和技术侦查行为有一定的区别。     

论我国刑事初查制度的缺陷及改革方向

我国的刑事初查制度在司法实践形成并发挥了打击犯罪的积极作用,但由于缺乏明确的法律依据和规范体系而存在诸多制度缺陷,从一开始就备受争议。从根本上克服这一缺陷不能仅从完善初查制度本身入手,而应考虑改革我国的立案程序,建立随机型刑事侦查模式。