On the morning of 11 January Mostafa Ahmadi Roshan, the deputy head of Iran's uranium enrichment facility at Natanz, was in his car on his way to work when he was blown up by a magnetic bomb attached to his car door. He was 32 and married with a young son. He wasn't armed, or anywhere near a battlefield.

Since 2010, three other Iranian nuclear scientists have been killed in similar circumstances, including Darioush Rezaeinejad, a 35-year-old electronics expert shot dead outside his daughter's nursery in Tehran last July. But instead of outrage or condemnation, we have been treated to expressions of undisguised glee.

"On occasion, scientists working on the nuclear programme in Iran turn up dead," bragged the Republican nomination candidate Rick Santorum in October. "I think that's a wonderful thing, candidly." On the day of Roshan's death, Israel's military spokesman, Brigadier General Yoav Mordechai, announced on Facebook: "I don't know who settled the score with the Iranian scientist, but I certainly am not shedding a tear" – a sentiment echoed by the historian Michael Burleigh in the Daily Telegraph: "I shall not shed any tears whenever one of these scientists encounters the unforgiving men on motorbikes."