Atlanta: At least 14 nuclear scientists are believed to be among those killed in Israel’s Operation Rising Lion, launched on June 13, 2025, ostensibly to destroy or degrade Iran’s nuclear programme and military capabilities.
Deliberately targeting scientists in this way aims to disrupt Iran’s knowledge base and continuity in nuclear expertise.
Among those assassinated were Mohammad Mehdi Tehranchi, a theoretical physicist and head of Iran’s Islamic Azad University, and Fereydoun Abbasi-Davani, a nuclear engineer who led Iran’s Atomic Energy Organisation.
Collectively, these experts in physics and engineering were potential successors to Mohsen Fakhrizadeh, widely regarded as the architect of the Iranian nuclear programme, who was assassinated in a November 2020 attack many blame on Israel.
As two political scientists writing a book about state targeting of scientists as a counter-proliferation tool, we understand well that nuclear scientists have been targeted since the nuclear age began. We have gathered data on nearly 100 instances of what we call “scientist targeting” from 1944 through 2025.
The most recent assassination campaign against Iranian scientists is different from many of the earlier episodes in a few key ways.
Israel’s recent attack targeted multiple nuclear experts and took place simultaneously with military force to destroy Iran’s nuclear facilities, air defences and energy infrastructure.
Also, unlike previous covert operations, Israel immediately claimed responsibility for the assassinations.
But our research indicates that targeting scientists may not be effective for counter-proliferation.
While removing individual expertise may delay nuclear acquisition, targeting alone is unlikely to destroy a programme outright and could even increase a country’s desire for nuclear weapons.
Further, targeting scientists may trigger blowback given concerns regarding legality and morality.
In our data set, we classified “targeting” as cases in which scientists were captured, threatened, injured or killed as nations tried to prevent adversaries from acquiring weapons of mass destruction.
Over time, at least four countries have targeted scientists working on nine national nuclear programmes.
The United States and Israel have allegedly carried out the most attacks on nuclear scientists. But the United Kingdom and Soviet Union have also been behind such attacks.
Meanwhile, scientists working for the Egyptian, Iranian and Iraqi nuclear programmes have been the most frequent targets since 1950. Since 2007 and prior to the current Israeli operation, 10 scientists involved in the Iranian nuclear program were killed in attacks.
Other countries’ nationals have also been targeted: In 1980, Mossad, Israel’s intelligence service, allegedly bombed Italian engineer Mario Fiorelli’s home and his firm, SNIA Techint, as a warning to Europeans involved in the Iraqi nuclear project.
Given this history, the fact that Israel attacked Iran’s nuclear programme is not itself surprising.
Indeed, it has been a strategic goal of successive Israeli prime ministers to prevent Iran from acquiring nuclear weapons, and experts had been warning of the increased likelihood of an Israeli military operation since mid-2024, due to regional dynamics and Iranian nuclear development.
By then, the balance of power in the Middle East had changed dramatically. Israel systematically degraded the leadership and infrastructure of Iranian proxies Hamas and Hezbollah.
It later destroyed Iranian air defences around Tehran and near key nuclear
installations.