STORY: The World Health Organization (WHO) is still working to identify the origins of the COVID-19 pandemic, its director general said last week, after a U.S. agency was reported to have assessed the pandemic had likely been caused by a Chinese laboratory leak.

Jamie Metzl, a senior fellow at the Atlantic Council who was also invited to testify at the hearing on Wednesday, said "there can be no doubt that a research-related origin remains a very serious possibility."

"There is no smoking gun proving a lab origin hypothesis, but the growing body of circumstantial evidence suggests a gun that, at the very least, is warm to the touch," said Metzl.