China's supreme court has overturned the death sentence of a woman convicted of killing her husband after she endured months of domestic abuse, a member of her family said. The US-based rights group the Dui Hua Foundation hailed the court's decision as "a landmark ruling with far-reaching implications for survivors of domestic violence". The Supreme People's Court reversed its approval of the death sentence given to 43-year-old Li Yan from Sichuan , her brother Li Dehuai said. He said he had first learned of the ruling in a letter sent by his sister from prison. "A court official told me the verdict was returned sometime in May," Li Dehuai said. Li added he did not know why the court had made the surprise decision or when the court in Sichuan would schedule a retrial. Li Yan's conviction became a landmark case in a decade-long campaign for comprehensive legislation on domestic violence. Her husband, Tan Yong, had beaten Li, extinguished cigarettes on her face and locked her out on their balcony in winter, according to the defence lawyer's earlier statements. In November 2010, a drunken Tan threatened to shoot Li with an air rifle, then he beat and kicked her. She hit him over the head with the gun barrel, accidentally killing him. Li then dismembered the body. She was arrested after a friend she confided in about the killing informed the police. John Kamm, the founder and director of the Dui Hua Foundation, said: "In China, if a woman is repeatedly abused and kills the man reacting to the abuse, she will be sentenced to death," he said. "This ruling reverses the trend. I don't think the [Sichuan] High Court will sentence Li Yan to death again. She will not be executed."