A Chinese research lab at the centre of a conspiracy theory over the origins of Covid had a "serious biocontainment incident" months before the pandemic started, a new report claims.
The Wuhan Institute of Virology was also understaffed and marred with safety issues, according to a Senate investigation.
The 329-page report consists of two years of work and claims the first death from the virus was in September 2019, two months earlier than first thought.
And that the country's government allegedly tried to hide the outbreak from the world.
The findings have no conclusive proof Covid came from the lab, though do include new circumstantial evidence.
The report, led by Senate Intel ranking member Marco Rubio, says: "A careful reading of reports from the WIV spanning more than a three-year period yielded a picture of a struggling institution: underfunded, underregulated, and understaffed."
It admits that it does not contain any one ''smoking gun" crucially linking the outbreak to the lab.
The report goes back to July 2019 when a WIV official warned of the "current shortcomings and foundational problems in the construction, operation, and maintenance" of the complex and directed staff to "prioritize solving the urgent problems we are facing".
On September 19, 2019 the lab shut down its online virus database in the middle of the night, the report claims.
Six days later it informed Wuhan airport it was carrying out a drill in case of an outbreak of a "novel coronavirus".
Days after that a Wuhan resident - referred to as 'Su' - died from what a biostatistician believes was Covid-19, the report adds.
In October, it says Chinese legislature was drafting biosecurity law and noted "currently the biosecurity situation in our country is grim" and listed "laboratories that leak biological agents" as a threat.
The following month the government was 'hiding' documented cases of the virus, the report claims.
Chinese Communist Party (CCP) officials then published a report warning: "Once you have opened the stores test tubes, it is just as if having opened Pandora's Box. These viruses come without a shadow and leave without a trace."
A CCP official then traveled from Beijing to Wuhan with instructions from President Xi Jinping on the "complex and grave situation currently facing safety work", the report claims.
The government failed to alert the World Health Organisation of the outbreak of what was a virus of "unknown etiology", until the following January.
In reference to actions taken by China in February 2020, the report goes on to say: "Just as Beijing was denying the possibility that COVID-19 came from a lab on the world stage, it was warning its own officials of such risks and rolling out new measures to prevent lab accidents."
Chinese scientists filed a patent for a Covid-19 vaccine on February 24, 2020 and the report claims findings imply work started no later than November the previous year.
What's more, Xi gave a speech to the country's politburo the same month referring to a link "between the political security of the party-state, public health, and better regulation of biosafety and biosecurity".
The Chinese Ministry of Science and Technology also issued further regulations addressing a long-lasting mechanism to prevent and control biosafety risks".
The report questions if Chinese authorities believed the spread of the virus stemmed back to the Huanan Seafood Market in Wuhan, why they took the time to address biosecurity conditions, while "mobilising all-hands-on-deck" at such an acute stage of the outbreak.
China has always insisted the WIV leak theory has no truth.
