Based on unspecified new intelligence, US Energy Department now thinks lab leak theory most likely explanation for pandemic, but expresses 'low confidence' over finding

Study co-author had previously called on scientific community to be more open to idea that coronavirus may have leaked from lab, but says now convinced otherwise

In new article, virologist Michael Worobey says his research 'provides strong evidence of a live-animal market origin of the pandemic,' rather than from a laboratory leak

Investigation hindered by China's lack of cooperation but most agencies believe virus not genetically engineered

The assessment could not verify whether the virus came from a Wuhan lab, or jumped from animals to humans as initially suspected

Wuhan lab denies any leaks; White House criticized Beijing's reaction as 'irresponsible and frankly dangerous,' saying this is not a time to be 'stonewalling'

WSJ says secret report by Lawrence Livermore National Laboratory makes strong case for further investigation into theory that says COVID-19 seeped from Chinese virology center

Move comes amid fresh US investigation into virus origins, including the possibility it was manufactured

US president asks intel officials to 'redouble' efforts to find source of virus, says world must 'press China to participate in a full, transparent, evidence-based' probe

Report cites undisclosed US intelligence document that says 3 workers at secretive laboratory that has been tied to coronavirus pandemic sought treatment in November 2019