The novel coronavirus "most likely" leaked from a lab in Wuhan, China, according to a bombshell report published Thursday by Republicans on the Senate, Health, Education, Labor and Pensions Committee, though the lawmakers underscore the findings lack indisputable evidence.
The report also concluded that China's unwillingness to cooperate with an investigation into the Wuhan Institute of Virology, the lab in question, means Beijing "no longer deserves the benefit of the doubt."
"Based on the analysis of the publicly available information, it appears reasonable to conclude that the COVID-19 pandemic was, more likely than not, the result of a research-related incident," they wrote.
"Nearly three years after the COVID-19 pandemic began, critical evidence that would prove that the emergence of SARS-CoV-2 and resulting COVID-19 pandemic was caused by a natural zoonotic spillover is missing," they added.
Lack of transparency from China, "prevents reaching a more definitive conclusion," the senators said.
"The hypothesis of a natural zoonotic origin no longer deserves the benefit of the doubt, or the presumption of accuracy."
More than 6.6 million people have died worldwide from COVID-19.
Sen. Richard Burr, R-N.C., the panel's ranking member who released the report, said it was critical the U.S. "continue international efforts to uncover additional information regarding the origins of this deadly virus."
China on Thursday locked down part of Wuhan in a scramble to halt widening COVID-19 outbreaks.