TOKYO -- Around midnight Sunday, as China was winding down its weeklong National Day holidays, Xinhua News Agency carried a one-line statement that sent shock waves through the international community.

Issued by the nation's anti-corruption authorities, it said, "Meng Hongwei, vice minister of Public Security, is being investigated by China's National Supervisory Commission for suspected violations of laws."

The bombshell ended speculation about Meng, who also served as the president of Interpol, the first Chinese citizen to hold the prestigious position.

Interpol is a Lyon, France-based international police agency that 190 member countries and regions count on for help in tracking down fugitives.

Meng had returned home for a visit in late September when his family, back in Lyon, lost contact with him. His wife eventually reported Meng's disappearance to French police.

The abrupt disappearance of Interpol's top official sparked global intrigue that, with the announcement of Meng being detained in China, became an uproar.

Security is tight in Beijing, in front of the Ministry of Public Security, which was once under the control of Zhou Yongkang. Now officials say they must alleviate the "poison" Zhou left behind.

On Monday, China's Ministry of Public Security, where Meng is a vice minister, issued a separate statement accusing the 64-year old of taking bribes and being engaged in other corrupt practices. But the accusations were a far cry from the explanation that the international community is looking for.

Subsequently, the Chinese government notified Interpol of Meng's resignation, which left the organization's other top officials scratching their heads. Meng still had two years to go on a four-year term.

Under standard Chinese operating procedure, detentions are not supposed to attract the spotlight. But Beijing was caught off guard by Meng's wife, Grace, who reported her husband missing to French police and sought protection for the rest of her family.

Normally, when dignitaries are detained in China, their wives are also held. Their silence is usually bought with assurances of a decent life going forward.

After returning to China and sensing danger, Meng texted his wife a single emoji, that of a knife. The message was loud and clear.

In addition to reporting her husband's disappearance to French police, Grace held a news conference in Lyon, hiding her face as a safety precaution.

By going public, Grace made it impossible for Chinese authorities to secretly deal with Meng. This time, it seems, Chinese authorities miscalculated, and Meng's detention became an international cause celebre.

What made Chinese leadership feel the need to suddenly detain the Interpol president and risk international criticism?

What happened exactly five years ago holds the key to solving the mystery.

China celebrates its National Day on Oct. 1. On that occasion in 2013, Zhou Yongkang made what would be his last public appearance, on the campus of the China University of Petroleum, his alma mater. Soon thereafter Zhou disappeared from the public eye.

Zhou is a former member of the Politburo Standing Committee, the Chinese Communist Party's top decision-making body. He once controlled the country's internal security apparatus, which includes the police. Meng served under Zhou for years.

Zhou was formally detained in December 2013. His wife, a former presenter at state-run China Central Television, was also deprived of her freedom. Zhou's detention marked the beginning of President Xi Jinping's signature anti-corruption campaign, a fierce weapon Xi has been wielding against his political foes.

Zhou Yongkang attends his sentencing in Tianjin, China, in this still image taken from video provided by China Central Television and shot on June 11, 2015.   © AP

Chinese authorities announced Zhou's detention to the general public more than half a year later. Zhou was eventually sentenced to life in prison.

Five years have passed since Zhou's last public appearance, but China's political environment remains the same.

Last October, at the Chinese Communist Party's 19th national congress, Xi's political faction, it is said, won an internal tug of war with the personnel changes it pushed through.

Still, he will not have a cakewalk to the national congress in four years' time and toward maintaining his all-important status as the top leader of the Chinese Communist Party.

Xi will be 69 when the next national congress convenes. There is a long-standing party rule requiring those who have reached the age of 68 to retire without assuming any new posts. If Xi strictly complies with the rule and resigns from the Central Committee, he could be forced to retire.

This may be why Meng, who is said to wield power in China's public security and police apparatus, has been targeted by Xi's anti-corruption drive five years after Zhou fell victim to it.

After taking the party's helm, Xi prioritized seizing control of the People's Liberation Army, which is the party's military.

After an anti-corruption crackdown, a sweeping reorganization and senior personnel changes, Xi largely accomplished this.

But Xi remains concerned about China's public security and police authorities, whose power is only surpassed by China's military.

The president is following the same script he used to go after the military. Five years ago, he began by cracking down on two former top uniformed officers, one in charge of military administration and the other in charge of operations.

Through these measures, Xi cleared the military of senior officers who are not truly loyal to him. 

Chinese President Xi Jinping has restarted his signature anti-corruption campaign in earnest as he begins preparing for the Chinese Communist Party's national congress in the autumn of 2022.

Now China's public security and police authorities are stressing the need to thoroughly eliminate the lingering "poison," or negative impact, of the Zhou era.

In the early hours of Monday, the Ministry of Public Security held an emergency meeting at which participants referred to "subversive activities by hostile forces." It was an unusual move and reminiscent of the height of the anti-corruption campaign five years ago.

Interpol has played an important role in Xi's anti-corruption campaign. It is closely related to Xi's "fox hunt" campaign, meant to capture "corrupt elements" who have fled abroad.

This is why Xi attended Interpol's 86th general assembly in Beijing in September 2017, along with Meng, and even delivered a keynote speech.

On the other hand, Interpol has also accumulated information that is unfavorable to Xi. Had Meng discovered there was a move afoot to detain him, he could have brandished this information and sought political asylum. Doing so would have dealt a serious blow to Xi, who took a big risk in detaining Meng after recalling him from Lyon.

There is a possibility that the Ministry of Public Security is about to experience a storm of purges.

Like Meng, Wang Xiaohong also serves as a vice minister for public security. Wang hails from Fujian Province. When Xi served a stint in the province, he and Wang built a close relationship. Later, Xi gave Wang the key post in the central government.

Xi trusts only people he knows well. This shows in the personnel moves Xi has made. And therefore, Wang Xiaohong is expected to play a key role as the president's faction cements its power base within China's police organizations going forward.

In this regard, Meng's sensational case highlights how Xi's China puts party politics ahead of international responsibilities.

China dispatched Meng to Interpol two years ago, which means any baggage Meng might be carrying was not an issue then.

The political storm triggered by Xi's anti-corruption campaign was thought to have abated. Any such view that existed within the party and government have now been quickly erased. The Meng Hongwei case has struck like a bolt out of the blue.