A 16-year-old Chinese girl starved her mother to death after tying her to a chair for a week, in fury at being sent to an Internet addiction treatment center where she was beaten and mistreated, Chinese media reported.

Treatment centers aimed at curing teens of Internet addiction or other behavioral problems have become  popular in China, but many are poorly regulated, military-style “boot camps,” where corporal punishment is common, media reports say. They have become increasingly controversial since a series of scandals broke in recent years.

The girl from northern Heilongjiang province killed her mother Friday, according to Thepaper.cn. She had previously stabbed her father with a knife after a dispute. He was hospitalized.

The girl's parents had become increasingly concerned about her behavior after she dropped out of school. On the suggestion of an aunt, they decided to send their daughter to the camp, which claims to have cured 7,000 children of Internet addiction in the past two decades.

In February, the girl was forcibly taken away by two strange men in a car and driven to the camp in faraway Shandong province, only escaping four months later, the paper reported. In an online journal, she later complained that trainers had beaten students for no reason and ordered those who did not behave to eat in front of the pit latrine.

In a journal post published on Aug. 25, she wrote:  “When you mentioned it to your relatives, they all said: 'Isn’t it all in the past? We love you, you should forget all those things.'”

“I am angry. People point at my nose and call me unfilial and worse than a beast,” she wrote. “It was them who sent me there. It was them who cursed me and beat me, it was them who sabotaged my life and libeled my character; but it was also them who said they loved me. My friends here, if it were you, what would you do?”

The post went on: “I will use their money to practice boxing and martial arts, and ambush them later. I will make them disabled, if not die.”

The girl shot photographs and video of her mother tied up in the chair, demanding thousands of dollars from her aunt to release her, ostensibly so she could go to a physics school in the city of Harbin. The money was sent, but by then the girl discovered her mother was already dying. She called an ambulance, but it arrived too late to save her mother.

Thepaper.cn said it had received calls from several students at the camp since running the story. The students complained of being beaten, cursed at and insulted, and even being watched when using the bathroom.

“When the toilets clogged up, students were asked to empty the toilets with their hands,” one former student said, according to Thepaper.cn. “You get beaten up in the toilet, and get beaten up again if you dare say no. You get beaten up if you are found to be in a relationship.”

Officials from Shandong told the paper they had sent a team to investigate the reports.

A series of scandals have erupted in previous years over the treatment of students at similar camps in China. In 2014, a 19-year-old woman died at a treatment center in central Henan province after being given “training” that involved being lifted off the ground and then dropped, the South China Morning Post (SCMP) reported, while another suffered head and neck injuries. Instructors suspected the woman was feigning injury and continued to kick her on the ground, the SCMP said, quoting a China National Radio report.

Other students told the radio station that corporal punishment was common at the camp in Henan and that some were ordered to stand still all night or lie on their stomachs in snow-covered fields in the winter. Some were so desperate that they threw rescue notes out of the windows of the center, which was subsequently closed down.

In 2009, a 15-year-old boy from southern Guangxi province died after being beaten by trainers two days after arriving a camp treating Internet addiction, the SCMP said.

China’s Health Ministry has banned the use of physical punishment at such centers, as well as the use of electro-shock treatment, to treat Internet addiction.

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