They beat her, bound her and led her from home. She knelt before the crowds as they denounced her. Then they loaded her on to a truck, drove her to the outskirts of town and shot her.

Fang Zhongmou's execution for political crimes during the Cultural Revolution was commonplace in its brutality but more shocking to outsiders in one regard: her accusers were her husband and their 16-year-old child.

More than four decades on, Fang's son is seeking to atone by telling her story and calling for the preservation of her grave in their home town of Guzhen, central Anhui province, as a cultural relic....