The mother was the first to leave. Perhaps it was domestic abuse that drove her away. Or perhaps it was simply the hopelessness in Cizhu, a village in Guizhou, one of China’s poorest provinces.

One way or another, Ren Xifen abandoned home in 2013. Her husband, Zhang Fangqi, walked out shortly afterward to find work.

They left behind more than a broken marriage, however. Cooped up inside the dusty house were four children, ages 5 to 13. Without their parents, the four siblings would have to fend for themselves.

They didn’t last long.

For two years, the boy and his three younger sisters survived on little more than corn flour, according to one Chinese newspaper. Abandoned by their parents, the children’s personalities changed. They shut themselves inside the cluttered house and refused to open the door even to visiting relatives, the New York Times reported. About a month ago, the kids stopped going to school.

When the doors finally did open on Tuesday, tragedy came tumbling out.

At about 11 p.m., a passerby found the oldest child sprawled out in front of the family’s house, suffering convulsions, according to Agence France-Presse. Neighbors soon found the other three siblings in similar conditions nearby. All four eventually died.

The four children drank pesticide in an apparent suicide pact, Chinese state media reported.

“Thanks for your kindness. I know you mean well for us, but we should go now,” read a note left inside the home, according to the Guardian, citing Xinhua, China’s official news agency.

“I made a vow that I wouldn’t live over the age of 15,” the note reportedly said. “I’m 14 now. I dream about death, and yet that dream never comes true. Today it must finally come true.”

Chinese police told Xinhua that they had analyzed the handwriting to determine that the boy had written the note, according to the Guardian.

The horrific child suicides have provoked criticism of the absent parents.

“The children did not lack food and clothes, but lacked the love and care of parents,” Xiao Wenying, a distant relative, said. “The parents failed to fulfill their parental responsibilities.”

Popular outrage has been checked, however, by how widespread the practice is in China of parents leaving their children at home while working in distant cities.

China has about 250 million migrant workers, most of whom are drawn from rural villages like Cizhu to mega cities where they can find manufacturing jobs, William Wan wrote in The Washington Post in 2013. Strict government rules and a shortage of schools in big cities mean that many parents leave their kids with grandparents or on their own.

There are roughly 61 million of these “left-behind children,” according to a 2010 China census. More than a third of all kids in rural China live without their parents. Nationwide, nearly 22 percent of Chinese kids have been left behind.

Debate rages over the costs and benefits of this system. “Many migrant parents believe they are fulfilling their duty to raise their family’s standard of living. Income sent home helps pay for better food and education, and some workers save enough money to build a new home in their rural village,” the Wall Street Journal noted in an article on left-behind children last year.

“Parents of left-behind children do not leave them without a careful consideration of the options they have available to them,” noted a 2011 dissertation by Wei Lu.

But “their absence forces children to shoulder the responsibilities of running a household,” the Wall Street Journal also noted. And Wei found that left-behind children performed poorly in school. “The drop in school performance could be the result of lack of supervision, additional housework duties, or the distracted attention of children caused by missing their parents,” Wei wrote. “The impact of their parents’ absence can affect children’s educational achievement either directly or indirectly.”

Another recent study found that left-behind students suffered severe social issues because of their abandonment. “Without parental care or accompany, the left-behind children tend to show some level of timidity and anxiety or some kind of aggressive and destructive performance in school,” wrote Hou Yuna in a 2014 paper. “The left-behind children are in the sensitive and critical period of growth, thus their academic and socio-psychological development cause extensive concern from the whole society.”

In recent years, China has tried to improve social services in rural areas, particularly for left-behind children. But Tuesday’s macabre mass suicide has moved Chinese leaders to promise more sweeping changes.

On Friday, the day that the four children were cremated, almost a dozen local officials were suspended or punished over the suicides, according to the South China Morning Post. Criticism focused on why the kids were allowed to skip school. “Three officials, including the education bureau director of Bijie’s Qixingguan district, were suspended for investigation, while two village officials, including its party secretary, were removed from office,” the Morning Post reported. “Six others, including the principal and a teacher from the primary school where three of the children studied, have been punished.”

If “the family is not capable of or willing to take care of the children, the state should step in,” Chen Fucai, a child welfare specialist from the Shanghai Academy of Social Sciences, told the Guardian.

The suicides also drew a response from the country’s top politicians.

“Those who fail to act or pretend to act must be held responsible,” Premier Li Keqiang said. “Such a tragedy cannot be allowed to happen again.”

But Tuesday’s tragedy was already a carbon copy of an incident in 2012, when five left-behind boys died in the nearby city of Bijie. The boys, ages 9 to 13 and all related, died after starting a charcoal fire inside the trash dumpster in which they had been living. A journalist who wrote about the incident was imprisoned. A specific fund was set up to help left-behind children, but it doesn’t seem to have helped the suicide victims.

In the most recent mass child death, both the family and government have received blame. Officials had tried to call Zhang, the father, “more than 100 times” since Tuesday but had not been able to reach him, the Guardian reported. Both Zhang and his wife beat their children, according to a Guizhou Province report cited by the New York Times. “The beatings by the father were so brutal that the arm of the son, Zhang Qigang, was dislocated on one occasion, and his ears were torn, the report said,” according to the Times. Ren was also a target of her husband’s abuse, according to the report, and once ended up in the hospital.

“Lack of care and love at home had turned the children into loners,” wrote Wu Yixue in China Daily. “The death of minors resulting from parents’ failure to fulfill their parental responsibilities has also highlighted the need for the authorities to take practical measures, even pass legislation, to ensure that mothers and fathers fulfill their parental duties.

“On a broader level, the tragedy has revealed the astonishing lack of a sound social welfare system, especially in poor and remote rural areas. If a basic welfare system had been in place in Bijie and the local government had taken steps to help the children, as it had promised after the 2012 tragedy, four young lives could have been saved.”

On Friday, Ren finally returned home for only the second time in two years to see her children — shortly before their cremation.

“I had to come back for a final look at them,” Ren, 32, said between tears. She had spent the past two years working in a factory nearly 1,000 miles away, making toys her own kids would never touch. Ren said she left her children after a “long and bitter dispute” with her husband and feared violence if she returned.

“I am illiterate and cannot even write my own name,” she told Xinhua. “I wanted them to perform well in school, unlike me, living a hard life.”

“I did not shoulder my responsibility for them,” she said.