The substances called “pheromones” are infochemical compounds emitted and received by animals of the same species. Acting upon the central nervous system, they stimulate the limbic, neuroendocrine, and autonomic nervous systems, thus influencing the formation of a vegetative and behavioral response that is determined by the type of pheromone. This results in the production of moods, emotions, feelings, drives, memory, and subconscious actions. Within the information system that operates to preserve a given species, a special role is played by alarm pheromones. Alarm pheromones trigger numerous classic autonomic and behavioral anxiety reactions in animals. Rodents exposed to the smell of other stressed rats or a predator react with an increased vigilance, distinctly changed behavioral patterns, increased body temperature, accelerated heart rate, and changes in the immune system. It has also been determined that humans are capable of sensing the difference between a neutral smell and the scent of fear. Infochemical fear substances secreted by humans enhance cognitive abilities in other humans. The author of this paper is involved in research that is exploring the components of the infochemical substance of fear in rats and humans. Intense anxiety states are known to accompany violent deaths associated with criminal threats; however, they do not precede unexpected violent deaths. The ability of postmortem examinations to determine the presence or absence of fear pheromones active in the deceased’s body at the time of death can have significance for determining likely scenarios involved in the victim’s death. 134 references