The team of scientists who just returned from a WHO-sponsored trip to China have apparently concluded the lab lead hypothesis is very unlikely. But NBC News reports that the Biden administration is not backing away from the theory, at least not yet. The reason? Intelligence officials have seen non-public material that indicates China attempted to cover up the virus early on.

A spokesman for the Office of the Director of National Intelligence told NBC News the agency is standing by a public statement it issued in April, which said that that American intelligence agencies “will continue to rigorously examine emerging information and intelligence to determine whether the outbreak began through contact with infected animals or if it was the result of an accident at a laboratory in Wuhan.”…

A Western intelligence official who has seen classified material told NBC News the U.S. has substantial intelligence that has not been made public about actions the Chinese government took — related to the Wuhan lab and other issues — that were designed to obscure the origins of Covid-19 and conceal its early impact. A former U.S. official who has also seen the intelligence agreed that it was significant, if inconclusive.’

Both sources said the material, which they did not detail, did not add up to evidence that a lab accident occurred. But they said it raised enough circumstantial questions that analysts have been unable to rule out the lab scenario. U.S. intelligence officials declined to comment.

Even before U.S. officials started talking publicly about the possibility of a lab leak in China, China and Russia were pushing similar claims about America. Those efforts escalated last spring when Sec. State Pompeo said there was “significant evidence” (but not certainty) the virus originated in a Wuhan lab. The lab leak theory has mostly been ignored by media outlets but in early January New York magazine published a piece suggesting it deserved a second look.

The core of the lab leak argument is the remarkable coincidence that the first outbreak of the disease happened in Wuhan, which happens to have two labs that study bat coronaviruses. One of those labs, the Wuhan Institute of Virology had the closest known relative of COVID-19 and had previously been cited by US observers as having insufficient security. Those arguments are recapitulated by officials in the NBC story:

Intelligence officials counter that one key lab, the Wuhan Institute of Virology, removed from public view a database of 22,000 virus samples for security reasons, and has not allowed a detailed look at the lab’s notes or other records.

They say it’s suspicious that the virus outbreak arose in Wuhan, a hub of virus research in China, while the bats that commonly carry coronaviruses are typically found in caves a thousand miles from that city.

In addition, there’s also the fact that tests of animals found at the Wuhan wet market apparently revealed no animals that were positive for the virus, meaning the alleged transition animal that passed the virus to humans hasn’t been identified. There’s also the fact that the first cases of the virus in Wuhan don’t seem to have any connection to the market, suggesting it spread there but possibly didn’t originate there.

Here’s a report NBC News published two weeks ago about the virus database removed from the Chinese website. As you’ll see, while U.S. officials are balking at definitive statements, Chinese officials are not. They are saying this did not arise in China, embracing a frozen food theory of the outbreak’s origin which has little to no support outside China.