Whether he was an opposition figure or not is irrelevant to his involvement in Iran's nuclear program. One thing that you pro-opposition folks forget--the Iranian opposition is firmly behind Iran's nuclear program. It's a source of national pride that transcends Iran's local politics.
Firebomb thrown during demonstration in northern Israeli town of Umm al Fahm (Haaretz)
from the article: Iran: Israel, U.S. killed pro-Mousavi nuclear scientist