China has witnessed a series of assaults by knife-wielding attackers on schools in recent years. Many have been blamed on personal grudges or people with psychiatric problems:
April 30, 2010: A farmer attacked and injured five kindergarten students with a hammer in Shandong province's Weifang city before burning himself to death. The man struck a teacher who tried to block him and then used the hammer to attack the children. None of the children had life-threatening injuries.
April 29, 2010: A 47-year-old unemployed man attacked a classroom of 4-year-olds at a kindergarten in Jiangsu province, wounding 28 of them. Two teachers and a security guard were also hurt.
April 28, 2010: A man wielding a knife broke into a primary school in Leizhou city in Guangdong province in southern China and stabbed 18 students and a teacher.
April 12, 2010: Yang Jiaqin, 40, hacked to death a second grader and an elderly woman near an elementary school in Xizhen village of the southern Guangxi region. The attack came one day before Yang's family was scheduled to send him to a hospital for psychological treatment. He had been diagnosed with a mood disorder.
March 23, 2010: Zheng Minsheng, 42, killed eight children in a knife attack at the Nanping Experimental Elementary School in south China's Fujian province. Zheng was executed April 28.
March 2, 2009: Xu Ximei, 40, hacked two preschoolers, aged 4 and 6, to death with a kitchen knife and injured three other children and a grandmother at a primary school in Mazhan, a village in Guangdong province, and at a yard in the village. Xu was believed to be mentally disabled.
Feb. 24, 2008: Chen Wenzhen, a former student at the Leizhou No. 2 Middle School in Guangdong province, stabbed to death a boy and a girl, then killed himself. Chen had dropped out half a year earlier because he suffered from headaches and could not concentrate on his studies, state media said.
June, 2007: A man state media identified only by his surname, Su, broke into the Chiling Primary School in Longtang township in Guangdong and killed a 9-year-old boy with a kitchen knife. Three other students were seriously wounded. The attacker had been seen quarreling with the boy's parents in the past.
May 24, 2006: Yang Xinlong hacked a neighbor to death in the village of Luoying in central China's Henan province, then took 19 elementary school students hostage and killed one before police subdued him. Yang was hospitalized after police shot him when he refused to surrender.
Nov. 25, 2004: Yan Yiming, 21, broke into a Chinese high school dormitory and stabbed nine boys to death in Ruzhou, Henan province. Yan's mother turned him in to police after he attempted suicide on the day following the attack. He was executed two months later.
Aug. 4, 2004: Xu Heping, 51, a part-time gatekeeper at a Beijing kindergarten killed one student and slashed 14 others and three teachers. State media said at the time Xu had a history of schizophrenia. The attack, near the compound where President Hu Jintao and other Chinese leaders live and work, prompted the government to order stepped up security at schools nationwide.