The only way to determine if nCoV is out of the laboratory is to conduct an international investigation, according to experts.

On May 9, China's Foreign Ministry posted a 30-page statement on its website, continuing to refute allegations related to Covid-19 by the US side.

"To prove that nCoV is made from a laboratory, it is necessary to determine whether it actually appears in any laboratory in Wuhan," said Daniel Lucey, an expert in infectious diseases, Georgetown University.

Lucey has 17 years of research and teaching about diseases, including SARS, Ebola, MERS, H5N1.

According to Lucey, the review of nCoV appearing in the laboratory between September and November 2019 is "very important" as the outbreak from Wuhan last year spread to 212 countries and territories.

Lucey predicts that China has carried out investigations related to Covi-19, including nCoV origin.

In late January 2020, Chinese studies assessed the Covid-19 virus associated with samples of corona virus found in Chinese bats, but they were mutated before they spread to humans, according to CNN.

According to Lucey, 33 Chinese samples were obtained either from animals, or from humans, but the country did not publish them.

Milton Leitenberg, a bio-weapons expert, now at the University of Maryland, USA, asserts that the question of the origin of the nCoV is due to unfounded inference.

According to Leitenberg, it was Thach Chinh Le, a leading researcher at the Wuhan Institute of Virology (WIV), that asked "nCoV has escaped from WIV" in an interview with Scientific American in March.

"The only way to identify nCoV evidence from the lab is to conduct an investigation," Leitenberg said.

For an objective international investigation, Lucey of Georgetown University recommends that the team should consist of scientists, health officials from many countries, the World Health Organization (WHO) and China.

"Then the results of the investigation will be guaranteed to be reliable," Lucey said.

Regarding the scope of implementation, Lucey suggested that the investigation team should conduct surveys in laboratories, markets in Hubei and neighboring provinces.

"China doesn't even say what it did," Lucey said.

Lucey has written a scientific report, suggesting that countries can discuss the origin of nCoV at the meeting of the World Health Assembly (WHA), the WHO decision-making body, which took place on May 18.

Leitenberg expressed skepticism about China's cooperation in the nCoV origin investigation organization, saying that Beijing could reject this request when the US joined.

"If countries that are members of WHO and the UN make strong demands, China can accept cooperation in conducting investigations," Leitenberg said.