Senior Biden administration officials overseeing an intelligence review into the origins of the coronavirus now believe the theory that the virus accidentally escaped from a lab in Wuhan is at least as credible as the possibility that it emerged naturally in the wild – a dramatic shift from a year ago, when Democrats publicly downplayed the so-called lab leak theory. Still, more than halfway into President Joe Biden’s renewed 90-day push to find answers, the intelligence community remains firmly divided over whether the virus leaked from the Wuhan lab or jumped naturally from animals to humans in the wild, multiple sources familiar with the probe told CNN. Little new evidence has emerged to move the needle in one direction or another, these people said. But the fact that the lab leak theory is being seriously considered by top Biden officials is noteworthy and comes amid a growing openness to the idea even though most scientists who study coronaviruses and who have investigated the origins of the pandemic say the evidence strongly supports a natural origin. Current intelligence reinforces the belief that the virus most likely originated naturally, from animal-human contact and was not deliberately engineered, the sources said. But that does not preclude the possibility that the virus was the result of an accidental leak from the Wuhan Institute of Virology, where coronavirus research was being conducted on bats – although many scientists familiar with the research say such a leak is unlikely. On Thursday, the director-general of the World Health Organization Tedros Adhanom Ghebreyesus said it had been “premature” to dismiss the possibility that a lab leak had spawned the pandemic and urged China to provide “direct information on what the situation of these labs was before and at the start of the pandemic.” Also on Thursday, China’s foreign ministry spokesperson released a statement saying that “since the beginning of the epidemic, China has taken a scientific, professional, serious and responsible attitude in tracing the origins of the virus.” As more US officials have come to see the lab leak theory as credible, their tone toward Beijing has also become firmer. Days after Biden announced the renewed probe, White House press secretary Jen Psaki told reporters that the administration had been pressuring Chinese officials through diplomatic channels to allow international investigators full access to the data China collected in the early days of the outbreak. For their part, scientists who have found strong genetic evidence that the virus came from an animal say they also would like access to what China knows about the beginnings of the pandemic, saying they can’t make their case without access to early samples. As the review has progressed, however, the White House has begun making public threats as well. National security adviser Jake Sullivan warned Beijing of potential consequences last month, telling Fox News that China will face “isolation in the international community” if it does not cooperate with probes moving forward. He told CNN’s State of the Union that same day that “if it turns out that China refuses to live up to its international obligations, we will have to consider our responses at that point.” A source familiar with the ongoing review said that several top administration officials, including Sullivan, view the accidental lab leak theory as equally plausible to the natural origins theory. Intelligence agencies that were skeptical of the lab leak theory a year ago, like the CIA, also now view it as a credible line of inquiry, this person said. “There has been a shift in their point of view,” this person added. But officials emphasized that no conclusions have been reached, and Sullivan has been highly cautious in reserving judgment until the review is complete. ‘Key intelligence needs’ While many individual officials hold their own personal opinions as to the likely origin of the pandemic, with some finding the lab leak theory more credible than others as they continue to receive and interpret the intelligence, people familiar with the probe said no one official’s opinion is driving the pace or direction of the overall review. Political appointees have sought to give the intelligence community and national labs wide latitude to complete the review without dictating their findings, and US officials say CIA Director Bill Burns, Director of National Intelligence Avril Haines and other top intelligence officials are getting regular briefings on the progress. A memo distributed to the intelligence community on June 11 by the Office of the Director of National Intelligence, and obtained exclusively by CNN, tasked officials with obtaining more data on both the animal and lab leak theories, citing “key intelligence needs” that could help determine the origins of the virus. The memo called for more examination of several topics including any “detections of the virus in wild or domestic animals,” the “breadth of high-risk Chinese and regional wildlife activities,” any viruses that “could serve as the backbone for genetic engineering purposes,” and the “breadth of Chinese biological research and related activities.” The memo also called on the intelligence community to study the “breadth of Chinese actions that may have inhibited World Health Organization or other origins investigations.” Intel community still split The intelligence community has also been consulting with outside experts and examining raw information that may have been missed— including information the State Department had collected in the Trump administration — and analyzing more open source information, such as peer reviewed studies out of China, said a source with knowledge of the probe. People familiar with the progress of the review, however, said the intelligence community as a whole is still in much the same place it was when Biden ordered his review in late May: Two agencies assess with low to moderate confidence that the virus originated naturally, while one assesses with the same lukewarm confidence that it escaped from a lab. In an interview with CNN, Bill Evanina, the top counterintelligence official under President Donald Trump, said that early on the intelligence community did not prioritize determining the origins of Covid the way it has now with the 90-day review. “Identifying the origins of the pandemic probably did not rise to a level of weapons of mass destruction, or identifying the plans and intentions of foreign leaders,” Evanina said. The person familiar with the probe said there will likely not be a definitive answer as to Covid’s origins at the end of the 90-day review— instead, any final assessment will likely lay out both theories and evaluate their pros and cons. The source said the relationship with China is too delicate to make an endorsement of one theory over another without smoking gun evidence, which doesn’t exist right now. “As I’ve listened to the analysts, I really see why it is that they perceive these two theories as being in contest with each other, and why it’s very challenging for them to assess one over the other,” Haines, the national intelligence director, told Yahoo! News in late June. Asked directly if she had a feeling which competing possibility was more plausible, she replied: “I don’t.” Gaining traction For the better part of 2020, advocates for the lab leak theory had to fight against claims they were being xenophobic or racist — in part thanks to anti-Chinese rhetoric from then-President Trump, who embraced the theory. An inquiry launched last fall by Trump’s State Department, which sought to investigate whether China’s biological weapons program could have had a greater role in the pandemic’s origin in Wuhan, was shut down early on in the Biden administration. An open letter published in February 2020 in the Lancet, an influential scientific journal, also set the tone early by declaring the virus to have a natural origin. But the lab leak theory has gained more traction in recent months, especially following reports that the intelligence community found evidence that researchers at the Wuhan Institute of Virology fell seriously ill with a mysterious virus in November 2019 – although it’s not clear whether they contracted Covid-19 and no further evidence has emerged to corroborate that report. The existence of another classified report issued last year by researchers at the Lawrence Livermore National Laboratory, which concluded it was possible that Covid-19 might have leaked from a lab in Wuhan, also became public. Popular opinion has also shifted. A POLITICO-Harvard poll conducted earlier this month found that 52% of US adults now believe Covid-19 leaked from a lab, up from 29% in March 2020. “The growing public discourse has sharpened the [Science] Committee’s focus on several topics within our jurisdictional mandate,” said an aide to the House Committee on Science, Space and Technology, one of a handful of panels on Capitol Hill that is now actively investigating the matter. The search for evidence For now, sources say, both theories lack definitive evidence, and officials say we may never know the truth. “We’re hoping to find a smoking gun, but it might not happen,” Haines told Yahoo. Pandemics in the past have emerged from natural transmission through animals, known as zoonotic transmission, and it often takes months or years to discover the host that the virus passed through as it adapted to infect humans. In some cases, as in Ebola, the original natural source has never been identified. It took years to find the evidence that an animal called a civet was the source of the 2003-2004 SARS outbreak. Despite tests of thousands of animals, the host for SARS-CoV-2 has yet to be found – but scientists say China’s not giving them the access they need to find the source. But there is also no smoking gun for the lab leak theory, according to multiple sources. Still, the renewed acknowledgment of the lab leak theory, coupled with fierce political interest on Capitol Hill, has spawned a number of congressional investigations that advocates say have developed new evidence. Rep. Michael McCaul, the top Republican on the House Foreign Affairs Committee, plans to release a Covid-19 origins report at the end of this month that stitches together a narrative of the lab leak theory and makes “a pretty declarative statement,” according to a congressional aide. “I believe we have found the answer to the question,” McCaul proclaimed at a recent GOP hearing on the pandemic’s origins.