Scientists released a pair of extensive studies on Saturday that point to a market in Wuhan, China, as the origin of the coronavirus pandemic. The two reports, totaling about 150 pages, have not yet been published in a scientific journal.

The researchers analyzed data from a range of sources to look for clues to how the pandemic arose. They concluded that the coronavirus was present in live mammals sold in the Huanan Seafood Wholesale Market in late 2019. The research suggests that the virus very likely twice spilled over into people working or shopping at the market. The researchers said they found no support for an alternate hypothesis that the coronavirus escaped from a lab in Wuhan.

“When you look at all of the evidence together, it’s an extraordinarily clear picture that the pandemic started at the Huanan market,” said Michael Worobey, an evolutionary biologist at the University of Arizona and a co-author of both studies.

The authors of the new study include researchers who previously published smaller reports that had pointed toward a similar conclusion, but based on much less detail.

Many of the first cases of COVID-19 clustered around the Huanan market. By the end of December 2019, hospitals in Wuhan had found dozens of cases of viral pneumonia.

The market was closed on Jan. 1, 2020, the same day that hundreds of thousands of people left Wuhan to travel back to their hometowns for the Lunar New Year. Millions more left the city in January, seeding local outbreaks across China.

This article originally appeared in The New York Times.

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