The whereabouts of vice-minister of state security Dong Jingwei has become a hot topic on Chinese and Western social media in recent days amid suggestions the top spy has spilled possible secrets on the Wuhan Institute of Virology – the highly-secretive lab at the centre of an audacious theory the pandemic began following a virus leak.
The rumour was detailed in SpyTalk, a publication reporting on US intelligence matters, which noted the claim he left for the US via Hong Kong in February with his daughter.
Adding confusion to the situation were claims from China Mr Dong appeared at a national security meeting on June 18.
An image of a man the South China Morning Post used in an article covering the event raised questions on Twitter as to whether it was actually Mr Dong.
With little clarity on the matter, Australian Foreign Minister Marise Payne declined to comment on the rumours when pressed on the ABC's Insiders on Sunday morning.
While noting the rumour remains unverified, prominent defector Dr Han Lianchao, a former Chinese foreign ministry official, said if true, the defection was "really a big bomb".
Renewed momentum for lab leak theory
Such a high-profile defection would prove devastating for Beijing and the rumour has given hope to the staunch supporters of the lab-leak theory that new evidence from the Wuhan Institute of Virology is on the horizon.
BBC foreign affairs correspondent John Simpson said if the rumour was true, "we could soon find out whether Covid really started in the Wuhan lab. And much, much more".
The leading theory, widely supported by experts globally, is the virus likely transmitted to humans from bats via an intermediate animal.
— John Schindler (@20committee) June 18, 2021
The lab-leak theory has gained momentum in recent months and was pushed by former US secretary of state Mike Pompeo who claimed the US has significant evidence the virus originated inside a lab.
Before leaving office in January, a month prior to Mr Dong's alleged defection, Mr Pompeo released a fact sheet detailing claims it had strong evidence to believe the virus was circulating among the lab's staff in Autumn.
Such a claim was later the centre of a report from The Wall Street Journal last month, which Foreign Ministry spokesperson Zhao Lijian said was "totally untrue".
And while relatively quiet on the origins of the virus at the beginning of his tenure as US president, Joe Biden has joined the calls for further investigations to determine whether the virus did in fact leak from the Wuhan Institute of Virology.
In the wake of the joint World Health Organisation-China mission looking into the origins of the virus, WHO chief Tedros Adhanom Ghebreyesus voiced concerns Western experts were not given key data during the trip earlier this year and the probe hastily dismissed the theory the virus leaked from a Wuhan lab, calling for immediate further investigations.
Do you have a story tip? Email: email@example.com.