Zhang Koukou was born on January 6, 1983, in Nanzheng County, Hanzhong, Shaanxi. On August 27, 1996, when he was 13, his mother Wang Xiuping died in a quarrel with the neighbouring Wang family, beaten by the family's 17-year-old third son Wang Zhengjun. She died in his arms, and her body was then publicly dissected on the road while several hundred people looked on. That December the Nanzheng County court convicted Wang Zhengjun of intentional injury and sentenced him to seven years because he was under 18, while also finding that the mother bore "a certain fault in how the case arose"; the Wang family was ordered to pay 9,639.30 yuan. Wang Zhengjun served only about three years and eleven months, the Zhang family said the sentence was too light, and the Wangs never said a word to them. For 22 years nobody gave him an answer. On Lunar New Year's Eve, February 15, 2018, Zhang, then 35, killed Wang Zhengjun, his brother Wang Xiaojun and their father Wang Zixin in the village, and turned himself in at a public security office on February 17. Hanzhong Intermediate Court sentenced him to death at first instance on January 8, 2019, the Shaanxi High Court upheld it on April 11, and on July 17 he was executed by the tyrannical CCP regime at the age of 36.
In Hanzhong, Shaanxi, Zhang Koukou attacked the Wang family in revenge for his mother being killed 22 years earlier and the murderer receiving a light sentence, killing three members of the Wang family. After the incident he turned himself in, and was executed the following year, sparking intense public discussion about judicial fairness and private revenge.
Zhang Koukou, a veteran from Hanzhong, Shaanxi, witnessed his mother beaten to death by local thugs as a child. In 2018 he returned home and killed several members of the family responsible, a case seen as a typical instance of folk revenge against village bullies and local tyrants.