The purpose of this paper is to formulate recommendations for the disclosure of biological traces in the laboratory and the handling of forensic evidence submitted for identification tests, recommended by the Polish Speaking Working Group of the International Society for Forensic Genetics. The paper organizes the knowledge of the most relevant stages of preliminary analysis of biological traces based on both literature sources and those resulting from years of research practice. Recommendations formulated in the course of multi-stage expert consultations contained in this study should be used in the development of laboratory procedures applied during the execution.

Aim of the study: Analysis of self-immolation cases and distribution of the resulting burns and their degree.

Material and methods: The study included 16 cases from the Department of Forensic Medicine, Jagiellonian University Medical College in Cracow from 2000-2022 in which the cause of death was self-immolation. Based on the analysis of photographs and autopsy reports, drawings were made showing the exact distribution and nature of the injuries, moreover, the approximate percentage of body surface area affected was determined as well as the frequency of involvement of specific areas of the body, and the presence of previous diseases and mental disorders including previous suicide attempts.

Results: 81% of victims were male. Two age groups were predominant among the cases analyzed, namely, individuals around the age of 20, and those between 50 and 60 years of age. 44% of the deceased had burns exceeding 80% of total body surface. The most frequently involved body areas were the extremities and chest as well as head and neck. Fourth-degree burns were most prevalent on the head and neck, third-degree burns prevailed on the upper and lower extremities, second-degree burns were mostly found on the chest, and first-degree burns - on the lower extremities. There were no cases of fourth-degree burns of the buttocks. 38% of the subjects had a history of substance abuse, 56% suffered from mental illnesses, whereas 31% attempted suicide in the past.

Conclusions: The distribution of burns in self-immolation cases is inhomogeneous. The most frequently affected area was the head, neck, chest and extremities, most likely due to victims dousing themselves with a flammable substance from the top of the head through the chest. In all cases, the immediate cause of death was burn disease, regardless of the size of the body surface area affected by the burns. The majority of victims had a history of mental illness, substance abuse or suicide attempts.

Aim of the study: Analysis of the choice of suicide method by gender and age of the deceased.

Material and methods: The study presented here was based on a retrospective analysis of autopsy reports from the years 2001-2010 in the Department of Forensic Medicine of the Jagiellonian University Collegium Medicum in Kraków. The basis of the research work conducted was the collection and extensive analysis of cases of suicide deaths. Subsequently, a preference analysis of the choice of suicide method was conducted, taking into account the age and gender of the deceased. The statistical analysis performed used logistic regression in Excel’s XLSTAT as an analysis tool.

Results: A total of 2,073 suicide cases were collected from the time frame under discussion. The predominant method of suicide was hanging (1524 cases, 1329 men and 195 women), the second most common method was jumping from the roof or window of a high floor of a building (jumping from heights; 171 cases, 100 men, 71 women). A statistically significant correlation of suicide method with gender was found for: hanging [odds ratio (OR) male (M) vs. female (F) = 3. 4; confidence interval (CI) = 2.7-4.3; p0.001]; drowning [OR: M/F =4.1; CI = 2.6-6.4; p0.001]; jumping from heights [OR: M/F=4.1; CI=2.9-5.7; p0.001] and poisoning [OR: M/F=3.2; CI = 2.1-4.9]. Suicide with the use of firearms occurred exclusively in the case of men (40 cases). The age of the victims correlated with the method of committing suicide by jumping from heights [0R=0.98; CI=0.97-0.99; p0.001] and rail suicide [OR=0.98; CI=0.96-0.99; p0.001].

Conclusions: The study revealed that both age and gender have a significant impact on the choice of suicide method. According to available epidemiological data and the authors’ predictions, a predominance of male over female sex was observed in the case of hanging, while jumping from heights was relatively more often chosen by women. The elderly were less likely to choose jumping from heights and rail suicide.

The study presents the results of research aimed at isolating the graphic features most frequently and least frequently modified by people committing autoforgery (self-forgery) of signatures in situations where the appearance of their natural signatures is not known to the recipient. The research covered a total of over 12,000 signatures from 200 individuals. The most successful attempts at autoforgery of legible and illegible signatures of each test subject were selected for the final evaluation. It was found that autoforgery changes are most often focused on the most striking features of the signatures, such as the structure of letters in the initial part of the signature, size, readability, impulse, and slope. Secondary features, more difficult to notice or those whose existence the writers are not aware of (such as the presence or absence of additions, the arrangement of letters in relation to each other, the shape and direction of signature lines, the format of legible signatures) are usually omitted in autoforgery activities. Detecting autoforgery can be a big challenge for experts, because in practice, any significant differences between the questioned signature and comparative signatures are often mistakenly considered to be the result of forgery. Therefore, in order to detect autoforgery, it is necessary to analyze the structure of easily noticeable features that most influence the so-called pictorial effect of the signature in combination with the unattractive features that remain unchanged in most cases of autoforgery. The more characteristic the latter are, the more their consistency in the questioned and comparative material proves self-forgery, regardless of the differences in the primary features. In the case of a forged signature, the opposite is true: the most easily noticeable features of the signature are imitated by the forger, and the differences occur mainly in secondary features.

Toilet cleaner containing hydrochloric acid is a common item found in households all over the world. Due to the availability of the substance, it becomes one of the main contributors to corrosive damage to the gastrointestinal system. This study reports a case of a female in her 50s with an alleged history of ingestion of toilet cleaner an empty bottle of which was found together with a suicide note at the incident site. During the autopsy, the forensic expert made an intriguing observation regarding the dispersion of ingested acid to other organs without gastric perforation. Despite the absence of gastric perforation, the corrosive effects of the ingested acid were evident in various organs, including the liver and spleen. This phenomenon suggests a unique mechanism by which the acid is able to disperse and cause damage beyond the stomach, leading to widespread organ involvement. However, through a comprehensive analysis of the detailed history, typical macroscopic autopsy findings, and chemical analysis reports, it is possible to establish that the cause of death is corrosive acid poisoning. In such cases, further investigation is warranted to gain a better understanding of the underlying mechanisms responsible for the dispersion of the acid and its clinical implications. By delving deeper into these aspects, we can enhance our knowledge and contribute to the field of forensic medicine.