https://jvi.asm.org/content/jvi/90/6/3253.full.pdf
"Isolation and Characterization of a Novel Bat Coronavirus Closely Related to the Direct Progenitor of Severe Acute Respiratory Syndrome Coronavirus"
an excerpt:
"In conclusion, we isolated and characterized a novel bat SLCoV isolate, WIV16, which is the closest ancestor to date of the SARS-CoV. Our results provide further evidence that Chinese horseshoe bats are natural reservoirs of SARS-CoVs. It should be noted that WIV16 is not the closest strain to the human SARSCoVs with regard to ORF8. Full-length ORF8 is present in several SARS-CoV genomes of early-phase patients, all civet SARS-CoVs, and bat SL-CoVs. It is split into two ORFs (ORF8a and -b) in most human SARS-CoVs from late-phase patients due to a deletion event in this part of the genome (3). Recently, two papers reported that they found a full-length ORF8 which has higher similarities to SARS-CoV GZ02 and civet SARS-CoV SZ3, suggesting that SASCoV derived from a complicated recombination and genetic evolution among different bat SL-CoVs"
Reading the paper, its clear that the Wuhan lab was studying viruses almost identical to the one that emerged in Wuhan. This would make sense, as this is what they are trying to prevent. But it also raises concerns about whether the epidemic in Wuhan originated from this lab.
Further evidence would be the fact that a member from the lab is reported to have contracted coranavirus.