Six former police officers attempted to kill themselves by drinking poison outside the main compound of China’s top leaders, activists said Friday, in an act of desperation over alleged corruption and wrongdoing by local leaders.

The former officers were quickly detained by authorities Thursday morning and rushed to local hospitals, according to others in their group. News of their arrest and pictures circulating Friday were quickly deleted by censors — a frequent occurrence because of China’s sensitivity to all protests.

The six are part of a group that calls itself “China’s Wronged Officers,” a loose affiliation of about 300 members claiming they were fired or prosecuted unfairly as a result of corruption or abuse in their local departments.

More than a dozen in the group who live on the outskirts of Beijing talked to The Washington Post in recent weeks about their experiences, and two were arrested in retaliation for those interviews.

The six — who belonged to another contingent from China’s northernmost province, Heilongjiang — timed their attempted suicides to coincide with China’s first Constitution Day, recently created by leaders to promote the idea that rule of law exists in China.

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Reports conflicted about whether the six swallowed a liquid pesticide or rat poison.

A former officer who founded the group, He Zuhua, said he was shocked by the suicide attempts. The former officers from Heilongjiang had not warned him or others of their plans, perhaps for fear authorities might catch wind and stop them.

The six had long complained of being fired unfairly without pay or health insurance.

“They’re desperate, with no way to sustain themselves,” said another former officer, Tian Lan. “They lost their family and are living a life without dignity. Their cases have been ignored for years. They feel they have no way out, except death.”

While many in the group have discussed protest via suicide before — often out of frustration — Thursday was the first time anyone attempted it. Drinking pesticide has become a common form of protest among Chinese farmers, especially after local leaders have forced them off their land.

According to other former officers who have talked to the poison drinkers or have seen pictures of the incident, the Heilongjiang contingent arrived Thursday morning in front of Zhongnanhai — a secretive, sensitive compound where President Xi Jinping’s office is located. They tried to unfurl a protest banner and were quickly intercepted by police.

In view of the police, before they could be stopped, the six downed the poison. A seventh person was responsible for taking photos and sending news of their protest, said He, who founded the Wronged Officers group in 2004 after being imprisoned, he says, for uncovering corrupt prosecutors.

Calls to four cellphones Friday went unanswered. Automatic messages said the service was cut or phones were turned off. Two of the former officers, who were reached by Washington-based Radio Free Asia, said they were sent to Peking University’s People’s Hospital.

One of the group said in the report that by killing themselves they hoped to grab the public’s attention and force the government to face its injustice. “I have chronic leukemia. There is no way out except to die fighting,” he said.

A woman answering the phone at People’s Hospital on Friday said she heard a group suffering from poison had been admitted but didn’t know their condition. Police in Beijing and Heilongjiang declined to comment.

Thursday’s Constitution Day — which had schoolchildren across China reading aloud from the constitution — was also marked by authorities arresting activists and preventing them from entering Tiananmen Square.

Some people online, noting the irony, pointed to Article 35, in which the constitution guarantees “freedom of speech, of the press, of assembly, of association, of procession and of demonstration.”

In recent months, increasing numbers in the Wronged Officers group have argued for more extreme measures, said Tian, one of the former officers.

But Tian said he has tried to talk some out of suicide. “You can’t make your case and clear your name if you are dead,” she said.

She said she last spoke with one of the six poison drinkers named Wang Binsheng just three days earlier. At the time, Wang told her he was planning a trip to Beijing and wanted to bring delicacies from his hometown for Tian. She told him to save his money.

“If you don’t want anything this time,” Tian recalls Wang saying, “you will not be able to have it again.”