the statement from shi zhengli — a virologist who's spent years studying forms of coronavirus — camenth to start its investigation into the origins of covid—19. but as our china correspondent john sudworth reports, the chinese authorities appear to be far less keen on scrutiny. the origins of this pandemic may well lie in the jungle covered hills of china's yunnan province. but reporting here is not easy. we're constantly followed and turned back at makeshift barriers and roadblocks. the bat populations here are known to harbour hundreds of coronaviruses, some of which can pass to humans. but it's the years of scientific research collecting those viruses in yunnan‘s caves that is suddenly highly sensitive. because many of the samples were taken back to this laboratory, almost 1,000 miles away, in wuhan. suggestions the virus leaked from here have so far been met with angry denials. but now the lead scientist, professor shi zhengli, when asked by the bbc whether she would welcome a formal investigation, replied by e—mail. she is correct, of course. with wuhan now back to normal, the g

the statement from shi zhengli, a virologist who's spent years studying forms of coronavirus, came aso travel to the city next month, to start its investigation into the origins of covid—19. but as our china correspondent john sudworth reports, the chinese authorities appear to be far less keen on scrutiny. the origins of this pandemic may well lie in the jungle covered hills of china's yunnan province. but reporting here is not easy. we're constantly followed and turned back at makeshift barriers and roadblocks. the bat populations here are known to harbour hundreds of coronaviruses, some of which can pass to humans. but it's the years of scientific research collecting those viruses in yunnan's caves that is suddenly highly sensitive. because many of the samples were taken back to this laboratory, almost 1,000 miles away, in wuhan. suggestions the virus leaked from here have so far been met with angry denials. but now the lead scientist, professor shi zhengli, when asked by the bbc whether she would welcome a formal investigation, replied by e—mail. she is correct, of course. with wu

the statement from shi zhengli, a virologist who's spent years studying forms of coronavirus, came asits investigation into the origins of covid—19. but as our china correspondent john sudworth reports, the chinese authorities appear to be far less keen on scrutiny. the origins of this pandemic may well lie in the jungle covered hills of china's yunnan province. but reporting here is not easy. we're constantly followed and turned back at makeshift barriers and roadblocks. the bat populations here are known to harbour hundreds of coronaviruses, some of which can pass to humans. but it's the years of scientific research collecting those viruses in yunnan's caves that is suddenly highly sensitive. because many of the samples were taken back to this laboratory, almost 1,000 miles away, in wuhan. suggestions the virus leaked from here have so far been met with angry denials. but now the lead scientist, professor shi zhengli, when asked by the bbc whether she would welcome a formal investigation, replied by e—mail. she is correct, of course. with wuhan now back to normal, the government is

but now the lead scientist, professor shi zhengli, when asked by the bbc whether she would welcome ahan now back to normal, the government is busy promoting another theory, that the virus didn't come from china at all. it is unlikely to have much appetite for a lab investigation, but nor, it seems, do some members of the who team as they prepare to begin their mission. i've yet to see any evidence at all of a lab leak or a lab involvement in this outbreak. and i have seen substantial evidence that these are naturally occurring phenomena, driven by human encroachment into wildlife habitat, which is clearly on display across south east asia. many scientists agree that a natural origin is the most likely, with the bat virus perhaps passing to humans via another animal in a wuhan wet market. but some are starting to wonder why, one year on, china has published so little about any studies that might help prove it. of course they've done them. they have the capability, they have the intelligence, they have the resources. 12, 13 months out since the first recognised case of covid—19, and we

but now the lead scientist, professor shi zhengli, when asked by the bbc whether she would welcome a. she is correct, of course. with wuhan now back to normal, the government is busy promoting another theory, that the virus didn't come from china at all. it is unlikely to have much appetite for a lab investigation, but nor, it seems, do some members of the who team as they prepare to begin their mission. i've yet to see any evidence at all of a lab leak or a lab involvement in this outbreak. and i have seen substantial evidence that these are naturally occurring phenomena, driven by human encroachment into wildlife habitat, which is clearly on display across south—east asia. many scientists agree that a natural origin is the most likely, with the bat virus perhaps passing to humans via another animal in a wuhan wet market. but some are starting to wonder why, one year on, china has published so little about any studies that might help prove it. of course they've done them. they have the capability, they have the intelligence, they have the resources. 12, 13 months out since the first

xi zhengli's cell phone rang shortly thereafter. >> she got a call from her boss who said drop whatever're doing and come back to the lab right now. >> dr. shi is known in china as the bat woman. she's one of the world's leading experts on bat-borne diseases. >> she's the director of the center for emerging diseases at the wuhan institute of virology. >> it is a biological level 4 facility. biological four safety research is the highest level of containment that exists for studying pathogenic viruses. >> doctors feared the cluster of atypical pneumonia patients in wuhan might be infected with the same family of viruses that caused the 2003 outbreak of sars, severe acute respiratory syndrome. >> more and more people were getting infected. we started to see on chinese social media in particular, the concern was growing. >> in new york, ecohealth alliance, a nonprofit organization devoted to tracking emerging diseases, began to take notice. >> we started to get our first inkling that something unusual was happening by looking on to social media in china. they mentioned there was an unusual