The assassination of Mostafa Ahmadi Roshan, chemistry expert and director of the Natanz uranium enrichment facility in central Iran, is just one of many Iranian scientist assassinations.

The bomb explosion, which was set off by magnetic bombs attached to the car by two assailants on a motorcycle, killed Roshan and wounded two others, reported the Associated Press.

Iranian officials noted that the assassination method was similar to that used in killing of two other scientist and an attempted assassination of another in the past two years. Iran suspects that Israel's Mossad Intelligence service is behind these assassinations.

The Associated Press reported this morning that a column in the Kayhan newspaper by chief editor Hossein Shariatmadari called for revenge. "Assassinations of Israeli military and officials are easily possible," Shariatmadari wrote.

“I think there is reason to doubt the idea that all the hits have been carried out by Israel,” Karim Sadjadpour, an Iran expert at the Carnegie Endowment for International Peace told The New York Times. “It’s very puzzling that Iranian nuclear scientists, whose movements are likely carefully monitored by the state, can be executed in broad daylight, sometimes in rush-hour traffic, and their culprits never found.” He suspects that the Iranian government could be responsible for some of the scientists' deaths.

Regardless of who has been killing them, it's been going on for years.

July 2011

Darioush Rezaeinejad, who Iran's Mehr news agency reported had ties to Iran's nuclear program, was shot dead by gunmen in eastern Tehran. Iran's intelligence minister Heydar Moslehi denied Rezaeinejad connection to the nuclear program, reported Reuters.

Associated Press reported that Rezaeinejad was an electronics student, who "allegedly participated in developing high-voltage switches, a key component in setting off the explosions needed to trigger a nuclear warhead."

November 2010

Majid Shahriari, a member of the nuclear engineering faculty at Shahid Beheshti University in Tehran, was killed after riders on motorcycles attached magnetized bombs to his car, reported the Associated Press. His wife, who was in the car with him, was wounded. According to Ali Akbar Salehi, Iran's vice president in charge of the Atomic Energy Organization of Iran, Shahriari "was involved in one of the big AEOI projects, which is a source of pride for the Iranian nation."

On the same day, there was a similar attempt at assasination of Fereidoun Abbasi-Davani. Abbasi, now Iran's Vice President and Head of Atomic Energy Organization. Abbasi was on a 2007 UN sanctions list for suspected links to secret nuclear activity, reported the Associated Press.

January 2010

Masoud Ali Mohammadi, a senior physics professor, was killed when a motorcycle with a bomb exploded near his car as he was leaving for work, reported the Associated Press. A spokesman for the atomic agency, claimed that Ali Mohammadi "was not involved in the country's nuclear program."

January 2007

Ardeshir Hassanpour, an Iranian nuclear scientist working at a nuclear plant in Isfahan, was reported by private US intelligence firm Stratfor to have been killed by Mossad. Iranian state media reported the cause of his death as accidental "gas poisoning" and Iranian government stated that he was not involved in nuclear research, according to ABC News.