I'd start with the location of his septic tank.
Here’s the thing. It’s not all that hard to build a nuclear weapon, especially when you have 1 reactor operating and 4 more under construction.
The whole centrifuge approach is only for fission bombs, and pretty much all nuclear weapons in the world, including those of India and Pakistan, use Plutonium, which is not a centrifuge product. Rather, it is a spent nuclear fuel product.
Point being, there had been talk of them just being a few days or weeks or months away from a weapon for what, 20 years?
I suspect overall the whole nuclear weapon story is for media consumption and what the US really wants is to dictate Iran foreign policy, regardless of them allowing inspection of nuclear sites or not.