The Israeli military leader told the Foreign Affairs and Defense Committee on Tuesday that "2012 is expected to be a critical year for Iran." He cited "the confluence of efforts to advance the nuclear program, internal leadership changes, continued international pressure and things that happen to it unnaturally."

Gantz's testimony was leaked by a meeting participant who spoke on condition of anonymity because the testimony was closed.

Israeli officials in the past have spoken somewhat giddily of the "unnatural" setbacks that have plagued Iran's nuclear program. The timing of Gantz's testimony, just hours before Wednesday's assassination, was perhaps the strongest hint yet of Israeli involvement.