Official delays in releasing information on issues people find important is one of the main reasons rumors spread on the Internet, an expert said.

"Nowadays, most government departments prefer to debunk fake news after it's been circulating than to disclose the truth upfront," said Cheng Manli, a media professor at Peking University.

Such delays weaken the authority of official information and provide an opportunity for people with bad intentions to spread rumors, especially online.

Cheng was speaking the day after Beijing police detained a 28-year-old woman named Ma on suspicion of spreading rumors online about a young woman's death. Ma reportedly wrote in her micro blog that the woman was raped by seven shopping mall security guards before she was thrown off the building, and that police refused to investigate.

Yuan Liya, 22, of Lujiang county in Anhui province, was confirmed dead after she fell off from the seventh floor of a shopping mall on May 3. Her death was considered a suicide, Beijing police said at the time.

The police statement was released only after hundreds of people crowded outside the mall on Wednesday, calling on police to investigate the case.

On Thursday, police confirmed that Yuan's death was a suicide. No evidence was found to indicate she was raped or poisoned.

The mall has agreed to pay Yuan's family 400,000 yuan ($65,000) as compensation for "negligence" by its management.

After the mall closed at 5 pm that day, keepers did not check whether there were people still on the premises, allowing the woman to stay in the center, according to government representatives from Yuan's hometown who came to Beijing to help handle the incident.

"In the case of Yuan's death, the police failed to prevent rumors at the beginning and someone exploited that to set off public speculation," Cheng said. "The rumor is further damage to the victim and her family, and disturbed public order."

If police published more information about the case, maybe similar rumors would be reduced and even prevented, she added.

"Each government department should constantly disclose information that the public may doubt or be confused about instead of ignoring the public's questions and hiding vital details. The more detailed information authorities disclose, the fewer misunderstandings and rumors there will be," she said.

Ma has confessed and voiced regret for spreading rumors, police said, adding that the investigation of her case continues.

According to the Law on Public Security Administration Punishments, passed in 2006, spreading rumors and false reports is punishable by administrative detention for five to 10 days for disturbing public order. Culprits also face fines of up to 500 yuan.

In Korla, the Xinjiang Uygur autonomous region, four people were given five days' administrative detention for making up and spreading rumors about a non-existent murder case, police said on Wednesday.

On May 5, two people were injured in a brawl in a village in Korla. When a suspect went past the hospital where the two injured were seeking treatment, he overheard talk of the incident. After he went home that night, he reported on his micro blog that "two people were chopped to death". Later, three others also posted the rumor online.

The State Internet Information Office recently launched a nationwide campaign combating online rumors. Suspects, including the two who spread rumors about the outbreak of bird flu in Guizhou province, were dealt with and their micro blog accounts closed, the office said.

The office said the micro blog account of He Bing, vice-president of the School of Law at China University of Political Science and Law, was suspended for forwarding a rumor twice last week, Xinhua News Agency reported on Friday.

He Bing said neither the authority nor the service provider had informed him of the suspension. Also, he did not know how long his account, which has more than 460,000 followers, would be suspended.

The professor was punished for forwarding a rumor that a university graduate killed an official for shutting down the website he set up because it wasn't registered. The account that posted the information on Wednesday, which was proved to be a rumor in 2009, was permanently closed, Xinhua said.