The origins of COVID-19 is something out of a detective thriller: some experts believe it’s an open and shut case that the virus's origin is natural, while others are looking to open the cold case and check for fingerprints to uncover the origins of the virus keeping us indoors.
Unfounded speculation, mystery and online rumour making, this isn't a true crime series -- it's people's attempts to figure out the origins of COVID-19.
US secretary of state Mike Pompeo told America's ABC News on Sunday there was "significant" and "enormous" evidence to suggest the virus' origins were in a laboratory in the Chinese province of Wuhan.
"I think the whole world can see now, remember, China has a history of infecting the world and running substandard laboratories," Pompeo told ABC News.
Pompeo says the Chinese government's response to the virus was "a classic Communist disinformation effort. That created enormous risk".
"President Trump is very clear: we'll hold those responsible accountable."
The World Health Organization (WHO) has weighed in calling Pomepo's claim "speculative".
"We have not received any data-specific evidence from the U.S. government relating to the purported origin of the virus. So from our perspective, this remains speculative," Dr Mike Ryan, WHO's top emergencies expert said in an online press conference on Monday,
"So if that data and evidence is available, then it will be for the United States government to decide whether and when it can be shared," he said.
Investigation into the origins of COVID-19
In what could only be anticipated in a spy novel, the US intelligence community (IC) revealed in a statement last week they are rigorously examining information and intelligence surrounding the origins of the coronavirus.
The investigation will look to determine whether the outbreak of the coronavirus was a result of a lab experiment gone wrong, or through contact with infected animals.
"The intelligence community [IC] also concurs with the wide scientific consensus that the Covid-19 virus was not man made or genetically modified," the statement read.
So where does the truth lie in all of this?
We canvassed the views of leading experts to determine whether it is possible the virus started in a Wuhan lab.
Professor Edward Holmes specialises in infectious diseases and biosecurity at the University of Sydney. He says there is no evidence that SARS-CoV-2, the virus that causes COVID-19 in humans, originated in a laboratory in Wuhan.
Prof Holmes says the most likely origin of this virus is other coronaviruses that are common in wildlife, and routinely jump to new hosts.
There is a bat virus named RaTG13, which is the closest known relative of SARS-CoV-2, and is kept at the Wuhan Institute of Virology.
But before this becomes a eureka moment, Prof Holmes says RaTG13 was sampled from Yunnan, a different province of China to where COVID-19 first appeared. Not only that, the genome sequence divergence between the two viruses is the equivalent to an average of 50 years of evolutionary change.
"The abundance, diversity and evolution of coronaviruses in wildlife strongly suggests that SARS-CoV-2 is of natural origin," Prof Holmes said.
"However, a greater sampling of animal species in nature, including bats from Hubei province, is needed to resolve the exact origins of SARS-CoV-2."
Are we certain there's been no human involvement?
Not all experts are so sure that there's been no human intervention in the origins of COVID-19.
Nikolai Petrovsky is a Professor in the College of Medicine and Public Health at Flinders University. In his position as a research director at Vaxine Pty Ltd, he's working on a COVID-19 vaccine and expects to commence human clinical trials soon.
Prof Petrovsky is less convinced there was no human intervention in the origins of COVID-19. He says despite intensive search to find its origins, no natural virus matching has been found.
"This raises the very legitimate question of whether the COVID-19 virus might be the result of human intervention."
The genomic sequence of the virus doesn't reveal any artificial gene inserts, something Prof Petrovsky calls a hallmark of a gene jockey. He says the absence of the artificial inserts has been interpreted to mean this virus is not the result of human manipulation.
"This logic is incorrect as there are other ways in which humans can manipulate viruses and that is caused by natural selection," he said.
Prof Petrovsky believes it's plausible that the virus was created in the biosecurity facility in Wuhan, that he says had been cultivating exotic bat coronaviruses at the time - and this could have left the facility via accidental infection of a worker, or inappropriate waste disposal.
But how would it be possible to create this in the first place? He uses the example of a bat coronavirus that is not infectious to humans.
"[If you] force its selection by culturing it with cells that express human ACE2 receptors, such cells have been created many years ago to culture SARS coronaviruses," he said.
"You can force the bat virus to adapt to infect human cells via mutations in its spike protein, which would have the effect of increasing the strength of its binding to human ACE2.
"And inevitably reducing the strength of its binding to bat ACE2."
"All evidence so far points to the fact the COVID-19 virus is naturally derived and not man-made."
Professor Nigel McMillan is the Director in Infectious Diseases and Immunology at Menzies Health Institute Queensland. He says the genetic changes in the virus can be found in two other coronaviruses from bats and pangolins, and that these are the source hosts.
"All evidence so far points to the fact the COVID-19 virus is naturally derived and not man-made," Prof McMillan said.
Prof McMillan says designing sequence changes would make no sense, because all previous evidence would show it would make the virus worse.
"No system exists in the lab to make some of the changes found," he said.
And for Associate Professor Hassan Vally, an epidemiologist and senior lecturer at La Trobe University, the topic is entirely cut and dried.
"There is no substance to this claim and other conspiracy theories about the origin of COVID-19," he said.
"There actually is evidence to support the natural emergence of the novel coronavirus, with preliminary genotyping studies showing its relationship with other bat viruses. We have to be careful to not aid those irresponsibly using this global crisis for political point-scoring by giving any oxygen to these and other rumours."
This article was originally published on April 17 and updated on May 5.
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