This study examined the relationship between police officers and individuals involved in police investigations, focusing primarily on suspects, victims, and witnesses. First, preliminary attitudes toward the other party were discussed before the direct involvement of police officers and individuals under investigation. Next, the importance of police officers building rapport with individuals under investigation was discussed in the development of this relationship. Police officers’ strategies toward individuals under investigation who did not tell the truth were also examined. Furthermore, police officers’ considerations of the temporal and psychological burdens on victims and witnesses were discussed. Finally, three components were derived and illustrated as vital elements of the police officer’s approach to the individuals under police investigation: appropriateness and fairness of the investigative procedure, humanitarian attitude toward individuals under investigation, and reduction of burden on them. The discussions in the study are expected to prompt the examination of relationships between judicial officers and the individuals they engage with, as well as relationships in non-legal contexts.
