We need to be figuring out how to deal with that. Wondering where it came from is mostly neither here nor there.
We aren't going to magically stop doing lab experiments if we can know for certain that it started in a lab. If we can determine for certain that this jumped species, welp, it isn't the first time and it won't be the last.
No magic required, we can just stop. Or better yet and more realistic, update and enforce regulations on this type of research.
Personally, I don't care whether it was a lab or not. The fact we haven't disproven it means it's not all that unlikely, and I think we should reform research practices now. We don't need to prove it did happen if we already know it could happen.