Senate Republicans who investigated the origin of the virus that caused COVID-19 lay out how it could have started from a laboratory leak, although they underscore the findings lack indisputable evidence.

The report Republicans on the Senate Health, Education, Labor, and Pensions Committee released Thursday is the latest GOP attempt to pressure the Biden administration and congressional Democrats to consider more seriously the theory that COVID started in a lab.

Questions about the origins of COVID-19 have become an increasingly partisan issue. House Energy and Commerce Republicans have pressed the National Institutes of Health on the lab leak theory.

However, most scientists support the conclusion in a Science Magazine paper published in August that the virus jumped from animal to human, likely in the crowded wet markets in Wuhan, China.

“I worry, because the crowd that is pushing this narrative is not motivated by scientific fact,” Gigi Gronvall, an immunologist and senior scholar at the Johns Hopkins Center for Health Security said about the lab leak theory before seeing the report. She said her work concluded the science behind an animal trade origin is “very solid.”

The Senate HELP report summarizes publicly available, open-source information related to the potential origin of SARS-CoV-2, the virus that causes COVID-19. Sen. Richard Burr (R-N.C.), the panel’s ranking member, said he hopes the report will guide the World Health Organization and other international institutions and researchers.

“With COVID-19 still in our midst, it is critical that we continue international efforts to uncover additional information regarding the origins of this deadly virus,” Burr said.

Senate HELP Chair Patty Murray said Thursday she’s still committed to working with Burr on an investigation into the origins of COVID, although the report was released only by Burr’s staff.

Murray said “undertaking a full examination of how COVID-19 first emerged” is part of the bipartisan pandemic preparedness legislation (S. 3799) the HELP Committee approved in March.

But the bill called for an independent task force to investigate the origins of COVID-19. “It is absolutely critical we learn the lessons from this pandemic so that we never find ourselves in a similar situation again,” Murray said. “I remain committed to passing the PREVENT Pandemics Act, which advanced out of Committee with overwhelming bipartisan support.”