The Washington Post editorial board called for EcoHealth Alliance President Peter Daszak to testify before Congress about the origins of COVID-19, including the possibility it leaked from a Wuhan virology lab Daszak worked with for years.

Following revelations that, despite repeated denials, the National Institutes of Health did fund so-called "gain of function" coronavirus research in Wuhan through Daszak's nonprofit, the Post called Monday for him to explain a series of "unanswered questions."

The Post specifically called out Daszak, who was repeatedly cited in media fact-checks dispelling the lab leak theory last year in spite of his close relationship with the Wuhan Institute of Virology, for his lack of transparency while loudly pushing the natural origin theory for the virus.

PETER-DASZAK---COVID-INVESTIGATION---WUHAN-CHINA

Peter Daszak, a member of the World Health Organization (WHO) team tasked with investigating the origins of the coronavirus disease (COVID-19), uses his mobile phone at a hotel in Wuhan, Hubei province, China February 3, 2021. REUTERS/Thomas Peter/File Photo (REUTERS/Thomas Peter)

"Why did he not disclose his 2018 proposal to the Defense Advanced Research Projects Agency (DARPA) for research on bat coronaviruses with the WIV and others, which called for engineering a modification onto spike proteins of chimeric viruses that would make them infect human cells in the way the pandemic strain did? What does he know about the databases of viruses that WIV took offline in 2019 and never brought back? Does he know what research the WIV may have done on its own, during or after their collaboration? What was being done at WIV in the months before the pandemic?" the Post wrote.

PETER DASZAK CLAIMS NO EVIDENCE OF ‘LAB-LEAK THEORY’ BUT ADMITS THERE'S BEEN NO DEFINITIVE INVESTIGATION'

The British-American zoologist's nonprofit worked extensively with the Wuhan lab as part of a five-year research grant from the National Institutes of Health to study the risks posed to people by bat coronaviruses, including possible pandemics.

After the coronavirus began to ravage the globe, he organized a widely cited February 2020 letter in The Lancet from 27 scientists who "strongly condemn[ed] conspiracy theories suggesting that COVID-19 does not have a natural origin." It did not disclose to readers that Daszak's organization funded coronavirus research at the Wuhan lab, and at least three of those signers later stated a laboratory accident merited consideration.

The letter stated at the time, "We declare no competing interests."

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Peter Daszak, a member of the World Health Organisation (WHO) team tasked with investigating the origins of the coronavirus disease (COVID-19), looks on from the balcony of his hotel in Wuhan, Hubei province, China February 6, 2021. REUTERS/Aly Song (REUTERS/Aly Song)

The Post noted Daszak, the only American on the joint China-World Health Organization Commission that investigated the virus' origins earlier this year, had not responded to its questions about the EcoHealth Alliance's report on its 2018-19 research that included genetically manipulated viruses to test their infectivity.

PETER DASZAK'S ECOHEALTH ALLIANCE CHANNELED MONEY TO WUHAN LAB

"Although the NIH continues to insist this did not fit the definition of "gain of function" research, and could not have led to the pandemic strain, it certainly should have met the U.S. government’s own requirements for stricter oversight … Mr. Daszak must answer these questions before Congress. His grants were federal funds, and it is entirely appropriate for Congress to insist on accountability and transparency. He might also help the world understand what really happened in Wuhan," the Post wrote.

There is circumstantial evidence to back both the natural and lab-leak theories for COVID-19's origination. China has steadfastly denied the virus emerged from the lab and even spread conspiracy theories that it didn't originate in China. 

The Post's stern editorial is the latest sign of increased media curiosity in the lab-leak theory, which was widely considered a fringe and even "debunked theory" last year by major outlets, including the Post. In one "fact-check" video that concluded the lab-leak theory was "doubtful," the Post interviewed Daszak, who praised China for being "incredibly open" on studying the pandemic.

Peter Daszak and Thea Fischer, members of the World Health Organization (WHO) team tasked with investigating the origins of the coronavirus disease (COVID-19), sit in a car arriving at Wuhan Institute of Virology in Wuhan, Hubei province, China February 3, 2021. REUTERS/Thomas Peter

Peter Daszak and Thea Fischer, members of the World Health Organization (WHO) team tasked with investigating the origins of the coronavirus disease (COVID-19), sit in a car arriving at Wuhan Institute of Virology in Wuhan, Hubei province, China February 3, 2021. REUTERS/Thomas Peter (REUTERS/Thomas Peter)

CNN ANCHOR DEFENDS CALLING RAND PAUL AN ‘A--’ FOR GRILLING FAUCI ON WUHAN LAB FUNDING FOLLOWING NIH ADMISSION

It also reported last year that the theory of a laboratory origination was "debunked" in a story headlined, "Tom Cotton keeps repeating a coronavirus conspiracy theory that was already debunked." It issued a correction earlier this year.

"Earlier versions of this story and its headline inaccurately characterized comments by Sen. Tom Cotton (R-Ark.) regarding the origins of the coronavirus," the correction read at the top of the report. "The term 'debunked' and The Post’s use of ‘conspiracy theory’ have been removed because, then as now, there was no determination about the origins of the virus."

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The headline was changed to "Tom Cotton keeps repeating a coronavirus fringe theory that scientists have disputed."

Fox News' Joseph A. Wulfsohn contributed to this report.