Genome sequencing is the scientific method to determine the origin of covid-19.

A Cambridge scientist had declared that covid-19 in Wuhan was the type B virus that evolved from type A.  No type A was found in Wuhan.  SG has type C virus which evolved from type B.

Where is type A found then?  If scientists around the world do genome sequencing, they would uncover the truth which can trace the type A virus back to the US.  China had already traced covid-19 H38 to the US.

http://sg-stock.blogspot.com/2020/03/japan-and-russia-alleged-that-covid-19.html