A Chinese student activist group dedicated to Marxism announced on Tuesday that six of its members vanished, presumably into the clutches of the Chinese security apparatus, after they declared their intention to work alongside laborers on International Labor Day, better known as May Day.

CNN noted this sort of thing happens in China quite frequently as Marxist activists make themselves an irritant to Communist Party leader Xi Jinping and his updated vision of centrally controlled industrialism:

Since August 2018, left-wing students, including those from Beijing’s prestigious Peking University, have been detained across China apparently over their involvement in worker protests in different parts of the country. The Chinese government is highly sensitive to attempts to organize protests or support what it considers subversive messages. In most countries, International Labor Day is often marked by parades and demonstrations held by trade unions, but in China is generally regarded as a holiday, despite the country’s Marxist roots. The latest round of disappearances appears to have taken place in recent days, ahead of a speech Tuesday by President Xi Jinping in honor of the 100th anniversary of the May 4 student protests.

In the case at hand, a Marxist academic named Qiu Zhanxuan announced on social media that he would spend the International Labor Day holiday performing manual labor alongside China’s poorly-compensated migrant workforce, which has lately been growing more restless and less migratory.

Qiu predicted he might “disappear” as a result of his stunt, and began posting pictures of six ominous individuals he believed were plainclothes policemen on his tail. His social media posts ended abruptly, after which the activist group he works with announced that five other members had also gone missing. CNN was unable to contact any of the missing individuals by telephone.

A female student belonging to the same Marxist group was evidently kidnapped by security personnel out of her campus apartment on Sunday night. The school and local police both declined to comment on her disappearance.

CNN speculated Xi and his underlings are nervous about student activism because the May 4 student protest anniversary, which commemorates a major event in the history of modern China, will soon be followed by the 30th anniversary of the Tiananmen Square massacre, a major event Chinese citizens have been ordered to forget.

The New York Times thought student activists might become especially restless this year because the Chinese economy is slowing down, which tends to deflate Xi’s argument that his post-Marxist version of communism is too successful to be argued with.

Xi is counting on using the 100th anniversary of the 1919 student uprisings to either infuse young people with nationalist spirit or intimidate them out of committing “treason” by criticizing their government. Chinese professors have received warnings from the government that 2019 will be “no ordinary year.” The intensity of propaganda and surveillance directed at the younger generation suggests the Communist Party elders are deeply worried about losing their support.

The NYT talked to a Chinese high school freshman who marveled over the bravery of student demonstrators in 1919 but seemed thoroughly cowed out of emulating them.

“Protesting is out of the question. You’d get detained right away,” he said.