The Economist reports:

When a motorcycle was blown up by remote control in Tehran last month, killing Masoud Alimohammadi, a professor of physics, the regime blamed “the triangle of wickedness”—Israel, America and their “hired agents”.

It is no secret that America, Israel and European countries are seeking to impede Iran’s nuclear plans, overtly and covertly. Yet the assassination theory was widely dismissed. The professor’s known works on particle and theoretical physics did not seem central to Iran’s nuclear programme. And his name had appeared on a list of Iranian academics favouring Iran’s protest movement. So, ran the prevailing theory, Israel or America had little reason to kill him, though Iranian hardliners may have wanted to do so.

But listen to the whispers of Western spies and diplomats, and the Iranian regime may turn out to be right. Well-placed sources in two Western countries now say the professor was “one of the most important people involved in the programme”.

Such conclusions, admit some, are based on “imperfect insight” into the workings of Iran’s nuclear establishment that includes the public and ostensibly civil projects run by the Atomic Energy Organisation of Iran (AEOI) and an overlapping but secret organisation run by the ministry of defence that focuses more on turning fissile material into nuclear weapons.

The AEOI said it had not employed Mr Alimohammadi. Several Iran-watchers said they had never heard of him until his death. But a Western counter-proliferation source says he “is known to have worked closely” with two key figures in Iran’s ministry of defence, Mohsen Fakhrizadeh-Mahabadi and Fereidoun Abbasi-Davani. Both are on the UN’s sanctions list of Iranians whose assets are to be seized and whose travels must be reported to the UN.