Pavao Pavličić is one of the most productive Croatian authors, known for many published crime novels for adults and children. This paper will analyse his children's crime novels Trojica u Trnju, Zeleni tigar, Petlja, Lopovska uspavanka and Dva duga dana and for this purpose research of the available literature in the field of theory and history of children's literature will be carried out. At the beginning of the paper, it will be looked at the emergence of children's novels in the world and in Croatia, as well as at the popularization of crime novels suitable for children and young people, which is characterized by the undertaking of an investigation led by a group of children instead of adults. It will also be pointed out the importance of Pavličić in the popularization of children's crime novels in Croatia, because of which this genre began to be understood as artistically equally valuable to others. The rules of crime fiction, the VII observance of which often leads to success, will be analysed, and also space, time, fables, and the characters of the boys who follow the reader through the mentioned five novels will be analysed specifically. In the end, the mentioned determinants of Pavličić's novels were analysed and an answer was obtained as to whether such novels are suitable for preschool children. Due to their length, they are certainly too extensive for pre-school readers, but by gradually processing chapter by chapter, children are offered content that encourages their investigative nature, encourages the development of critical thinking through discussions about what they have read, and unconsciously educates them and encourages them to do noble actions and to fight for justice.