A classified study warning the Covid-19 pandemic might have spilled from a lab in Wuhan has resurfaced as a focal point with lawmakers wanting to revive the quest for answers, a report from The Wall Street Journal said.

According to four people familiar with the document, the study, released in May 2020 by researchers at the government-backed Lawrence Livermore National Laboratory, discovered the coronavirus could have escaped from a lab in Wuhan at a time when that line of inquiry was considered politically taboo.

However, the study has received new political clout as the notion the pandemic was caused by research conducted at the Wuhan Institute of Virology has acquired widespread acceptance in recent months.

According to those familiar with the study, it was prepared by Lawrence Livermore's intelligence arm, the "Z Division." Lawrence Livermore has extensive knowledge of biological concerns. They said their evaluation was based on genomic analysis of the SARS virus - which causes Covid.

The evaluation is said to be one of the first by the U.S. government to seriously consider the possibility that the virus spilled from Wuhan Institute of Virology, as well as the mainstream hypothesis the virus spread naturally from animals to humans.

Although several prominent scientists have recently asked for a more thorough investigation of the lab hypothesis, many scientists continue to believe that natural spillover is the most likely explanation.

However, emails acquired by The Washington Post and BuzzFeed revealed that National Institute of Allergy and Infectious Diseases Director Anthony Fauci was communicating with a scientist as early as January 2020 about the likelihood that SARS-CoV-2 was engineered in a lab.

Scientists last year argued the most credible explanation is the SARS virus's "natural emergence:" it leaped from bats, or an intermediary species, to humans in a random occurrence sometime in 2019. Many people still believe this way, and some have become even more certain of it.

Several news organizations also played down the notion the virus was caused by human error in 2020 after numerous experts with relevant experience described the idea as exceedingly implausible.

China's government has denied the virus escaped from the Wuhan lab and has said it is fully cooperating with international efforts to determine the origins of the pandemic.

The Wuhan Institute of Virology has also denied the virus escaped from its premises and stated that none of its employees tested positive for Covid.