Image caption The death of a young clothing worker triggered public outcry

Millions of Chinese internet users have posted online pledges not to kill themselves in recent days.

"I will never commit suicide," the postings say. "If I die unexpectedly, I was killed by others and the police should investigate the crime."

The pledges are a reaction to a woman's death that police concluded was suicide, despite rumours it was murder.

Some hope they will prevent authorities falsely ruling their death suicide if they die in suspicious circumstances.

With more than 20 million postings, "anti-suicide pledges" are now the second most popular topic on weibo, China's version of Twitter.

This developed after the suspicious death of Yuan Liya, a young clothing store worker in Beijing last week.

The woman's death was quickly ruled a suicide by police, but persistent rumours claimed the 22-year-old was gang-raped by security guards in the mall where she worked and then thrown from a high balcony.

Angry protesters demanded an investigation into the case, but they were quickly silenced by hordes of police.

In response, many ordinary people are attempting to protect themselves from what they fear could be a similar fate.

'Forced' suicide

Public pledges against committing suicide first surfaced in China last year, after prominent political dissident Li Wangyang reportedly hung himself in a hospital room, while police were reportedly guarding his door.

His family and friends say Mr Li's severe physical disabilities make the local government's explanation of his death impossible. They encouraged all China's activists to circulate anti-suicide pledges.

"I have no history of mental illness. No matter what bad situation I will be in the future, I will not commit suicide," writes Cheng Tao, a political cartoonist.

"If I die by accident, my death was engineered by other people. My internet friends, please pursue my case until the end. I have been invited to drink tea [a euphemism for a meeting with police] three times this year and my internet account has been deleted 18 times."

"It is not impossible this will happen to me. Please repost this and make your own promise to prevent 'forced' suicide."

Scores of other people are now following that advice.

"Even if I have no car, no house, no lover, no money for food, and even if I have Aids, I will not commit suicide or fall off a building voluntarily," one user named Initial-D writes.

"If I die unexpectedly, government departments can't blame a suicide on me."

The trend highlights the serious lack of trust that many in China place in public institutions, ranging from the police to the courts.

However morbid the anti-suicide pledges might seem, many in China believe they offer a shred of protection for themselves or for the ones they might leave behind.