House Republicans said Thursday that the genetic sequence for SARS-CoV-2, the virus that causes COVID-19, was isolated and mapped by researchers in China in late December 2019, two weeks before Beijing revealed the existence of the deadly virus to global public health authorities.

The revelation does not settle the debate on whether the virus originated from nature or was the result of a laboratory accident. It adds to suspicions, though, that China’s government knew more details about the virus in the earlier stages of the pandemic than it has let on.