Will Israel's Bomb Destroy The Evidence?

Israel is very worried about the possibility that Iran may be making bomb-grade uranium. All indicators suggest otherwise, but in the absence of Iran's cooperation with the UN's inspection regime, who is to know?

Israel is said to have about 100 nuclear bombs and the means to deliver them. Suppose they were to bomb the suspected nuclear sites into the dust? Destroy them completely.

How, then, would they ever prove that there was a problem? If they destroy the evidence, they will remain guilty of dropping a bomb, yet they will no longer have proof that they should have done so.