Maria's Son (1983)

Original title: Синът на Мария

A young journalist comes across interesting report material: talented marine engineer Maria died while on duty. Her story turns out to be quite a puzzle though - people who knew her are not willing to share much. Trying to make them speak, the journalist presents himself as her son. He hopes to dig up the truth about her and spares no effort, ending up at the bureau for investigation. The report he's writing never gets published but his belief system certainly gets challenged.