The Soundless Cry(1965)

Shinichi is not only poor, he is also deaf, and leads a joyless life with his sick mother. His one happiness is his friendship with a girl who works in a bar nearby. Then, one day, his mother dies after drinking the medicine that Shinichi himself gave her. It is discovered that the pills contained poison. He is apprehended on suspicion of murder and taken away for interrogation, unable to defend himself - being deaf and dumb - or even to proclaim his innocence.