Police in the Chinese capital have detained 67 people for disturbing social order after demonstrators gathered to stage a rare protest in Beijing, complaining that the government was unfairly targeting a charity.

While there are thousands of protests every year in China over everything from pollution to corruption, large protests are rare in heavily guarded and affluent Beijing, with the ruling Communist Party valuing stability above all else.

State news agency Xinhua said late last week police had detained executives from a company called Shanxinhui, accusing them of operating a pyramid scheme and duping people out of money in the name of raising funds to help the poor.

Beijing police said in a statement late on Wednesday that 67 of those involved in the protest, which led authorities to shut down a major road in a southern neighborhood of the city, had been detained.

Some of those involved, who were deemed not to be a great threat and who had repented, had been released after receiving “rule of law education”, it said. Those who planned and instigated the action would be punished in accordance with the law, police said.

The statement did not say whether any of the 67 had been released or how many may face prosecution.

Investors in the company, some of whom had also gathered in small groups on the street, told Reuters on Monday they had come to complain that Shanxinhui had been dealt a huge injustice and that it had genuinely helped a lot of poor people.

Beijing police subsequently warned it was against the law to organize “illegal gatherings” and those who did so would be punished.

The government has accused Shanxinhui of plotting, manipulating and persuading people into taking part in a pyramid scheme disguised as a charity and swindling them out of money.

The government has repeatedly vowed to crack down on financial crime and fraud.

Last year, Chinese authorities shut down peer-to-peer lender Ezubao over an online scam that state media said took in some 50 billion yuan ($7.40 billion) from about 900,000 investors.