What We Know About the U.S. Intelligence Community’s Split on COVID-19 Origins

News that the U.S. Department of Energy made a determination about the origins of COVID-19 has sparked new questions about the U.S. intelligence community’s investigation of the global pandemic that has killed an estimated 6.85 million people.

The Energy Department, which runs multiple national laboratories, concluded with a low level of confidence that COVID-19 most likely emerged as a result of a leak from a laboratory in China, the Wall Street Journal reported on Sunday, citing anonymous sources. The Journal reported that the Energy Department’s new determination was classified. Previously, the agency was undecided on the cause of the pandemic.

“Knowing how this pandemic started is absolutely vital to protecting our people,” says Andrew Weber, a former Assistant Secretary of Defense in charge of nuclear, chemical, biological weapons defense. “The fact that the intelligence community of the United States of America believes that both scenarios are plausible is enough to lead us to change some of our policies.”

Eight agencies, plus the National Intelligence Council, have investigated the causes of the virus, according to a report summary from the Office of the Director of National Intelligence released in August 2021. The details of these investigations, including specific methods and sources used to make the determinations, and even the names of the agencies involved, remain hidden from public view.

Based on what we do know from that report, the intelligence community remains divided on this issue. So far, two agencies believe the most likely cause of COVID-19 was a lab leak, at low and moderate confidence levels. Four agencies and the National Intelligence Council concluded with low confidence that COVID-19 emerged as a result of natural transmission from animals to humans, and two have yet to make a determination. The names of the agencies were not included in the report and U.S. officials have declined to provide specifics when asked by reporters and lawmakers.

“The President made trying to find the origins of COVID a priority when he came into office,” John Kirby, spokesman for the National Security Council, told reporters Monday at the White House. “He’s got a whole of government effort designed to do that. There is not a consensus right now in the U.S. government about exactly how COVID started. There is just not an intelligence community consensus.”

The Energy Department news comes ahead of a Tuesday House Oversight Committee roundtable titled “Preparing For the Future By Learning From the Past: Examining COVID Policy Decisions.” House Oversight Committee chair James Comer told reporters on Monday that he would try to get the Energy Department’s assessment declassified and share it with the public, according to Axios. According to Weber, releasing such information in a way that protects sources and methods could take weeks.

Here’s what we know about the divisions in the U.S. intelligence community over what caused COVID-19.

The lab leak theory

Alongside the Department of Energy, the Federal Bureau of Investigation backs the lab leak theory, according to the Journal report and one from CNN, which TIME has not verified. The FBI did not comment directly on either outlet’s reporting.

It is the only agency in the intelligence community that has made an assessment at a “moderate confidence” level, which indicates it is based on information credible enough to surpass a “low confidence” finding.

The 2021 report summary revealed that one agency determined with moderate confidence that the virus found its way into the human population after “a laboratory-associated incident, probably involving experimentation, animal handling, or sampling by the Wuhan Institute of Virology.” The document did not name the agency.

The natural transmission theory

The National Intelligence Council and four agencies of the U.S. intelligence community, which have not been publicly named, determined that COVID-19 likely spread to humans through natural transmission from an animal, according to the report summary. All five of those bodies made their rulings with low confidence.

Experts who back this theory base their conclusion on “China’s officials’ lack of foreknowledge,” as well as the historical precedent of new infectious diseases originating in animals.

For example, the SARS outbreak from 2002 to 2004, which infected around 8,000 people and killed at least 774, was traced back to civets in southern China. That outbreak was caused by a coronavirus—the same family of pathogens that includes COVID-19.

The disease that came to be known as COVID-19 was first acknowledged after the World Health Organization was informed of several cases of a mysterious viral pneumonia in the central Chinese city of Wuhan. According to the WHO, Chinese authorities said that some of those initial patients worked in a seafood market there, about 40 minutes from the Wuhan Institute of Virology, which had long conducted research on coronaviruses.

Still on the fence

At the time the government report summary was released in 2021, there were three intelligence community agencies undecided between the lab leak and natural transmission hypotheses. According to the Journal’s recent reporting, one of those was the Department of Energy, which now supports the lab leak theory.

The Journal and CNN have reported that the Central Intelligence Agency is one of the two remaining undecided groups, a fact TIME has not verified, while the other is still unknown.

Why they’re divided

According to the 2021 report, the divisions between agencies largely stem from the importance experts at these agencies place on different pieces of intelligence and available scientific evidence—especially given the limited clinical samples and epidemiological data they have to work with. Weber, who is now a senior fellow at the Council on Strategic Risks, says China is failing to cooperate in a meaningful way with the World Health Organization’s investigation into COVID-19 origins. “Clearly they’re withholding information, putting out disinformation,” he says.

But the divisions in the U.S. government could also come down to other differences. According to Weber, some intelligence agencies, like the Department of Energy, run labs that employ experts and state-of-the-art technology, meaning they may have access to more sophisticated science than agencies without those resources. And while the agencies are likely working with many of the same basic facts, it’s possible that some have access to information that others do not.

“We don’t always know that every agency’s getting the most sensitive information,” he says. “The hope would be that they’re sharing all the information they have, but I’m not certain that that’s happened.”

Even if the virus was naturally transmitted into the human population, the precedent set by older diseases indicates that it can take more than a decade to determine which species were probably responsible.

Even then, they don’t know with 100% certainty. Furthermore, China does not appear to be cooperating with the WHO’s investigation. That means it’s unlikely we’ll ever know for sure how COVID-19 originated, and the division within the U.S. government is likely to persist.

—With reporting by Brian Bennett