Many of the claims, thus far unsubstantiated, sound like something from a Hollywood thriller - that Zhou sanctioned a fatal hit-and-run accident involving his first wife so he could marry former CCTV anchor Jia Xiaoye ; or that Zhou conspired with other rogue elements in the leadership to harm and even overthrow President Xi Jinping , who came to power a year ago.

Some reports said Zhou and his cronies received hundreds of millions of yuan to allow jailed mobsters to walk free.

Others suggested that Zhou and his family have abused his power to accumulate illicit wealth ranging from 10 billion (HK12.3 billion) to 100 billion yuan, depending on the various versions circulating over the overseas Chinese websites.

Now, over the weekend, came suggestions that the leadership may finally publicly acknowledge the investigation into Zhou as early as this week.

According to the Beijing-backed newspaper the Central Commission for Discipline Inspection, the country's top anti-corruption watchdog, is scheduled to meet the press this week where officials may address the issue.

Even if that were the case, however, the officials may just acknowledge the investigation is under way without giving away further details.

Mainland leaders are believed to have worked very carefully on the wording of the public announcement of the investigation of Zhou as the case is not merely another anti-corruption probe but one with important implications for the party's unity and image.

Since Xi came to power, he has staked his presidency on fighting rampant official corruption, promising to tackle "tigers and flies" as part of his effort to consolidate power and enhance the legitimacy of the ruling Communist Party.

Over the past few months, nearly 20 senior officials with the rank of deputy government minister or above have been sacked and detained on corruption allegations.

But the investigation of Zhou has taken the fight to an unprecedented level - current or retired Politburo Standing Committee members were believed to be exempt from anti-corruption investigations since the Communists came to power in 1949.

China has come a long way since the 1950s and 1960s when Mao Zedong waged political struggles to purge his rivals at the highest level of the leadership.

Over the past two decades, however, the party leadership has ruled through consensus, which means that the Politburo Standing Committee members made collective decisions on all major important issues regarding the country's development and its foreign relations.

This explains the delicate handling of Zhou's case - leaders want to show their determination to fight corruption, but without giving the impression that targeting Zhou implies divisions at the highest level of leadership.

That probably means that even if Zhou were involved in political manoeuvring to challenge Xi, as widely speculated, that would unlikely be made public. Instead, the investigation is mostly likely to focus on abuse of power and corruption.

With the mainland leadership looking set to bring down Zhou, expectations are rising on whether they will also go after other former top leaders who are also widely believed to be involved in corruption.

That is unlikely. Widening the net to target other retired leaders could trigger an intense fight among factions within the party and lead to instability and disunity at a time when the leadership intends to use the anti-corruption drive to shore up the party's power.

Indeed, the decision to investigate Zhou came after the various party factions reached a consensus.

The investigation of Zhou presents a good opportunity for the leadership to not only win the support of a public disenchanted with corruption and injustice, but also to promote the rule of law by signalling that no one is beyond its reach.

So, instead of allowing speculation to grow wilder by the day, leaders should acknowledge as soon as possible that Zhou is under investigation. The transparency of the investigation and any following trial are even more important.