The investigation is a basic procedural evidentiary action intended for the presentation of evidence, ie means of proof. Today, more and more specialists of various professions and professional profiles are participating in the inspection in the role of the main participants in the inspection process. The complexity of actions during the investigation is not in the fact that material objects as carriers of information should be observed and fixed, but in the complexity and complexity of mental tasks that occur during the investigation as a result of observation. During the investigation, the conditions, characteristics and properties of the found material evidence are studied, which is brought in connection with the criminal event or crime. Violent death is death that has occurred under the circumstances of mechanical, asphyxiating, physical, and chemical injuries. Natural death is the result of the development of one or a combination of several diseases that led to the death of a person. The basic method used in the preparation of this paper was the analysis of the content of collected scientific and professional literature, by studying the Law and regulations for the field of labor analysis. For the preparation of this Final Thesis, search and collection, ie merging the collected materials into one quality unit, were selected as suitable methods. The methods of synthesis, induction, deduction and logical interpretation were used for the research. The paper is structured in nine complete chapters. The first chapter shows an introduction. The second chapter presents the objectives of the paper. The third chapter explains the investigation. The fourth chapter shows violent death. Chapter five explains the mechanical injuries and the clues that point to them. Chapter six shows and explains asphyxial injuries and the clues that point to them. Chapter 7 explains and shows the physical injuries and the clues that point to them. Chapter eight shows and explains the chemical injuries and the clues that point to them. Chapter 9 presents natural death and its most common causes. The last chapter presents the conclusion, followed by the literature, a summary in Croatian and English, a curriculum vitae and a statement of academic integrity.