Who leaked Israel's atomic secrets, years before Vanunu? Nuclear documents revealed

It's a forgotten chapter in Israel's history, now revealed in declassified documents. When Ben-Gurion worked to obtain a nuclear weapon for the country, he was opposed by a phalanx of intellectuals who decried the effort and even created a group to thwart it. Is it possible that they warned the U.S. about the nuclear project 20 years before whistleblower Vanunu did?