Zou Hengfu, a former professor at Peking University (PKU), published a very controversial post on his Sina Weibo account last week.

He claimed that some university officials and professors sexually assaulted attractive waitresses working in a campus restaurant. A spokesperson from PKU dismissed Zou's allegations as irresponsible and outrageous, partly attributing Zou's attack to revenge against PKU, since the university didn't extend Zou's contract several years ago.

Many extreme criticisms and verbal attacks have appeared on the Internet since Weibo gained popularity in China, but Zou's allegations are some of the most bizarre.

In fact, it's not difficult to find out the truth of the issue, since it has received massive online attention due to its close relation to the morality and school spirit of PKU.

PKU has asked the school's discipline and inspection authority to investigate the issue. But it's not enough.

The national discipline inspection and judicial authorities should investigate the issue and make an authoritative conclusion.

If Zou's accusations are well founded, those university officials and professors should be punished in accordance with the law. Otherwise, Zou should be liable for slandering others.

The case should be handled with special care. Either PKU or Zou should pay the price for stirring up public opinion.

Weibo in China is on its way to becoming a double-edged sword of social governance. It provides an unprecedented chance for freedom of speech and pushes China's democracy from the grass roots upward. But meanwhile, it creates room for rumor spreading and personal attacks.  

Zou may be a whistle-blower. He may also be a slanderer who is just using the Internet to vent his anger.

As Zou's allegations and the people involved are attention-catching, clarifying the truth of what happened could encourage online democratic supervision as well as hitting rumor spreaders.

Zou is one of the intellectual elite. If he truly participates in promoting supervision by public opinion, he deserves applause and he should be responsible for his words and deeds.

However, nowadays, the sources of supervision have become diverse. It needs to set up the authority of supervision. Only by this can slander, which is a free-rider of supervision, be isolated and reduced.

With the deepening of China's reform and opening-up, China's freedom of speech should be healthily broadened. It shouldn't cross the line to endanger society, nor should it be restrained due to over caution.

Accusations against PKU, one of China's most famous universities, have not been rare in recent years. The university's reputation has already been darkened. Zou's latest attack on the university shows the vulnerability of its image. The PKU should reflect on this.

China is now in a special historical period, in which it could reflect on everything or even demonize everything. At many times, it's hard to distinguish between expressing opinions and emotional outbursts. Defining social justice has encountered contradictions from the very beginning.

There are many ambiguities in society. The Chinese public needs to make these ambiguities clear, in case speculators want to manipulate the public's feelings.

The truth of Zou's accusations against PKU should be discovered and the public suspicions over the issue should be cleared up.

The author is a commentator with the Chinese edition of the Global Times. opinion@globaltimes.com.cn