out the door. and they continue want to figure out where you are going around the city. for us it is going to various places. it is going to the wuhan cdc. it was going to the one institute of theology, it was going -- to that four spot where this is all amplified. they were keeping close, trying to make sure that anyone we would speak with, they too would then stop trailing. so much so, wall, some of the folks we did interview, and these are people that dealt with a lot of pain, lost loved ones during covid. we hear further we wouldn't care for them for several days after we interviewed. them and it was very likely that they were being held and detained after talking with us. >> david culver, thanks for all your excellent reporting. we appreciate it very much. standby, we'll get back to you as well. i want to bring in our chief medical correspondent, doctor sanjay gupta with the latest on where the health community stands on the lab leak assessment. sanjay, right now they're basically two theories when it comes to the origins of this deadly coronavirus. it's spread from