A man from central China has been arrested for an alleged revenge attack on a former teacher he accused of viciously beating him almost 20 years ago, according to local media reports.
The suspect, identified only by his surname Chang, was detained by police on Thursday, after a video of the assault in Luoyang, Henan province, appeared on social media on Sunday.
In the footage, Chang is seen stopping an older man riding a moped in the city's Luanzhou county and asking him, "Do you remember me?"
He then begins slapping his victim, identified by his surname, Zhang, around the head and face. The attack lasts for about 20 minutes, during which time Zhang does not fight back but repeatedly says, "I'm sorry".
On Wednesday, a person claiming to be Chang, wrote on an online forum that he was responsible both for the attack, which happened in June, and recording it, but not for uploading it to social media.
The person wrote that Zhang, now aged 50, was Chang's English teacher in his second year of high school.
The alleged abuse happened when Zhang caught Chang sleeping during a lesson. After making him kneel at the front of the class, the teacher then kicked the boy "at least 10 times" in the head, the post said.
"I would like to apologise to all teachers, except Zhang," the person wrote, adding that the way he had been treated at school had left him traumatised and wanting revenge.
A day after the footage appeared online, police in Luanzhou said on Weibo - China's Twitter-like platform - that they had launched an investigation into the incident.
Chang was arrested at Hangzhou East railway station in east China's Zhejiang province, while buying a ticket for a train to Henan, local radio station The Sound of Zhejiang reported. It did not say what he had been doing in Hangzhou.
According to a report by Red Star News on Wednesday, Zhang told police that he did not file a complaint at the time of the assault because he felt ashamed.
His employer, Luanchuan Experimental Senior High School, confirmed Zhang had been attacked but said it was unaware of any students, past or present, holding a grudge against him, local newspaper Dahe Daily reported.
Corporal punishment in schools was banned in China in 1986, but cases of children being physically assaulted are not uncommon.
Earlier this month, three kindergarten teachers in northeast China's Liaoning province were detained on suspicion of physically abusing pupils in their care, including stabbing them with toothpicks.
In August, a kindergarten teacher was accused of kicking and slapping two of her charges and stepping on the face of a third while the child was napping.
This article was first published in the South China Morning Post.