Nuclear physics professor Masoud Ali Mohammadi, who was killed after a bomb blast in front of his house in northern Tehran Photograph: Fars News Agency/AP
Even for a country deep in political turmoil, the killing of Massoud Ali Mohammadi in Tehran today came as a shock. There have been arrests, disappearances and occasional shootings, but the manner of his death was as meticulous as it was disturbing.
Mohammadi was blown up outside his home in an smart northern suburb of Tehran by a remote-control bomb that had been attached to a motorcycle parked on the street. As his stunned neighbours cleared up the rubble they struggled to understand why a little-known academic would have fallen victim to such a highly professional assassination.
The answer may lie in Mohammadi's profession and political inclinations. He was a particle physicist and a supporter of the Iranian opposition movement, raising the possibility he had become the latest victim in a covert war over Iran's nuclear aspirations. It is a war in which scientists find themselves potential soft targets.
Over the past three years, another nuclear scientist has died in mysterious circumstances, and a third vanished without trace while visiting Saudi Arabia last June. In the same period, a former deputy defence minister and general in Iran's Revolutionary Guards also disappeared while on a visit to Istanbul.
The regime in Tehran has alleged the west is behind the disappearances, and was quick to blame the US and Israel for Mohammadi's death. "Given the fact that Massoud Ali Mohammadi was a nuclear scientist, the CIA and Mossad services and agents most likely have had a hand in it," Abbas Jafari Dolatabadi, Tehran's chief prosecutor, told a state news agency.
The state department in Washington dismissed the accusation. Its spokesman, Mark Toner, told journalists: "Charges of US involvement are absurd."
In online comments, Mohammadi's former students at the University of Tehran pointed to his role as a campus organiser of opposition protests against the disputed re-election of President Mahmoud Ahmadinejad last summer, and questioned what role he might have had in the nuclear programme as he was an expert on theoretical quantum physics rather than on nuclear fission.
Rahesabz, an online news service close to the leadership of the opposition "green movement", hinted at government involvement in the killing.
"Reliable sources say Dr Mohammadi was involved in Iranian defence programmes, including nuclear facility programmes and was in possession of classified information," the website reported. Meir Javedanfar, an Iranian-Israeli analyst and co-author of The Nuclear Sphinx of Tehran: Mahmoud Ahmadinejad and the State of Iran said it was "very, very unlikely" the regime killed Mohammadi. "It is the least likely option. It scares others from joining the nuclear programme," Javedanfar said. "If they wanted rid of him, they could have lifted him off the street, and the rest would have been history."
The killing comes at a critical time in long-running but largely unseen struggle between the west and Iran over the Islamic Republic's nuclear programme.
Diplomacy appears to be at a dead-end after Tehran refused to heed security council demands to suspend the enrichment of uranium, which Iran insists is for peaceful purposes but the west alleges is ultimately intended for nuclear weapons.
The US, Britain and France are canvassing support for further sanctions but meeting determined resistance led by China. Israeli officials have threatened to take pre-emptive military action, but privately acknowledge that attacks against deeply buried and highly secret targets would have no guarantee of success.
Against that background, a parallel, secret effort to disrupt Iran's nuclear progress looks increasingly like the only battle the west is winning. Amid anger and disillusion over last year's election, Iran's counter-intelligence department dedicated to defending the country's nuclear secrets, Oghab 2, is having increasing problems assuring the loyalty of scientists and officials. In February 2007, Ali Reza Asgari – a former Revolutionary Guard general who had risen to cabinet rank – checked into a hotel in Istanbul and promptly vanished. According to various accounts, he was either abducted or he defected, but there is general consensus he is now in the west providing a rich stream of intelligence.
A month earlier, a nuclear scientist named Ardeshir Hassanpour, 44, died in what was officially described as a gas poisoning incident but was widely reported as an assassination, possibly by Mossad.
Last June, Shahram Amiri, a nuclear physicist at Malek Ashtar University in Tehran went on a pilgrimage to Mecca and never returned. Iran said he was seized, but according to many reports, he defected.
Vincent Cannistraro, former head of operations at the CIA's counter-terrorism centre, said: "It is clear one of them, likely Amiri, is under a different identity living in the US and has been a major source of information. So it's possible the guy just assassinated in Tehran was killed by the Iranians fearing he was one source on the programme revealed by the defector."
The west's biggest intelligence coup to date was the discovery of a secret uranium enrichment plant near Qom. The discovery announced in September – largely due to information from defectors and informants in Iran – set back Iran's hopes of building a parallel nuclear fuel cycle.
Iran's leadership, temporarily unsettled by Qom's discovery, has recovered its resolve. In November Ahmadinejad vowed to build 10 enrichment programmes. The march of the programme continues alongside the campaign to stop it. Mohammadi is unlikely to be its last victim.
