Kansas Republican Sen. Roger Marshall is warning that a new virus could break out of China and cause another worldwide pandemic as he releases “Muddy Waters,” a comprehensive new report on the origins of the COVID-19 pandemic.

The ranking member of the Health, Education, Labor and Pensions Committee and staff reviewed more than 50,000 documents for the report, which found that the COVID-19 virus was created in a lab and the outbreak was likely the result of two unintentional lab leaks.

“This report concludes most likely this was two leaks,” Marshall said during a briefing with reporters ahead of the release of the report. “The possibility of a lab leak in the September-October [2019] time frame, even as early as July or August, was followed by vaccine development in November 2019. And then another lab leak seems to be the most sensible explanation in this retrospective review.”

The report determined that the U.S. government was funding gain-of-function research at the Wuhan Institute of Virology.