SHANGHAI (AP) — Police said Thursday they have detained two men suspected of threatening children following a wave of attacks at schools in China that prompted orders for police and security guards to watch over students as they enter and leave schools.

Liu Yongche, 39, was detained on May 2, a week after a local elementary school in Wuxi, west of Shanghai, received an anonymous letter demanding 100,000 yuan (about $14,700). It threatened to harm students and teachers if the money was not paid, said the deputy director of the Wuxi Public Security Bureau, who gave only his surname, Chen.

Chen said that Liu, a migrant worker from neighboring Anhui province, is under criminal detention. A government notice published in state media said Liu was short of cash due to gambling debts.

"I'm so poor and I hope your school could help me out by putting 100,000 yuan ($14,706) into my account... Otherwise, I'll have no other choice but to do it," the official Xinhua News Agency quoted the letter as saying. Liu threatened an attack similar to one in March in Nanping, in southeastern China's Fujian Province, where a man killed eight primary school children.

Phone calls to the school rang unanswered Thursday.

The second man, who was only identified by the surname Hu, was detained from Monday through Wednesday after posting a comment on an online bulletin board suggesting "to kill a kid to have some fun."

Hu, a 20-year-old, was not accused of committing a crime, Chen said.

"He was feeling empty inside and wanted to attract attention," he said.

Experts say the violence against children reflects a lack of support for the mentally ill and the huge social inequalities in China's fast-changing society.

The school attacks began with the stabbings in Nanping. The man convicted for that crime was executed on April 28, the same day a 33-year-old former teacher broke into a primary school in the southern city of Leizhou in Guangdong province and wounded 15 students and a teacher with a knife.

The next day in Taixing city in Jiangsu province, a 47-year-old unemployed man armed with an 8-inch (20-centimeter) knife wounded 29 kindergarten students — five seriously — plus two teachers and a security guard.

In the latest attack on children, a farmer hit five elementary students with a hammer Friday in the eastern city of Weifang before burning himself to death.

The government has sought to show it has the problem under control, mindful especially of worries among middle-class families who, limited in most cases to one child due to population control policies, invest huge amounts of money and effort to raise their offspring.


Associated Press researcher Zhao Liang in Beijing contributed to this report.