(NewsNation) — The U.S. Department of Energy reportedly believes the COVID-19 pandemic might have started with a Chinese lab leak, but that doesn’t mean they’re sold on the idea.

The new finding was first reported Sunday by the Wall Street Journal, which cited a classified intelligence document that was shared with White House officials and some members of Congress. New, undisclosed intelligence prompted the department to revise its opinion on the lab leak theory, now judging it with “low confidence” to be true.

A low confidence finding essentially means the evidence to support that theory is incomplete or questionable.

That’s according to the DNI website, which defines three tiers of confidence as part of an intelligence guide for first responders.

By the department’s definition, a low confidence assessment “means the information is scant, questionable, or very fragmented, so it is difficult to make solid analytic inferences; it could also mean that the (intelligence community) has significant concerns about or problems with the sources.”

Until now, the energy department was undecided on the pandemic’s origin. A low confidence designation, however, still leaves room for questioning, according to the Office of the Director of National Intelligence (DNI).

Reached by email Monday, an energy department spokesperson said they could neither confirm nor deny the accuracy of the WSJ’s report or the theory.

The FBI backs the lab theory with “moderate confidence.”

A finding of moderate confidence usually means the information could be interpreted differently and that the intelligence community has alternative views. It could also mean that the information is credible but needs more corroboration.

Dr. Peter Hotez of the Baylor College of Medicine told NewsNation that he’s skeptical about the Energy Department’s findings.

“Two back-to-back papers published in Science Magazine, one of our most important scientific journals, clearly showed that the initial cluster of (COVID-19) cases all centered around a wet market in Wuhan — which is the expected mode of transmission of coronaviruses,” he said.

Hotez said if the virus originated from a lab leak at the Wuhan Institute of Virology, there would have been a “random occurrence of cases all over Wuhan.”

National Security Council Spokesman John Kirby told reporters Monday that there “has not been a definitive conclusion” surrounding the 2020 outbreak and declined to speculate further.

Not all federal agencies are on board with the lab leak theory.

The National Intelligence Council, for example, has low confidence that the initial COVID-19 infection was most likely caused by natural exposure to an infected animal, while the CIA remains undecided.

None of the agencies support the theory that the virus was used as a biological weapon.

Chinese Foreign Ministry spokeswoman Mao Ning denied the lab leak theory Monday, saying, “Certain parties should stop rehashing the ‘lab leak’ narrative, stop smearing China and stop politicizing origins-tracing.”

NewsNation Producer Steven Joachim contributed to this report.