When the young daughter of police captain Richard Malinowski is raped and murdered, his colleagues hastily find a suspect called Daniel Eckman. Despite there being no witnesses and no forensic evidence, he is sentenced to 30 years. From jail he starts writing to the policeman, expressing his deep regret for the death of the daughter and proclaiming his innocence. Doubts begin to surface in the mind of the policeman, who begins his own private enquiry. He finds that Salinas, a known serial killer of children, was in the area at the time of the killing.