The motorcycle chained to the tree in front of Mansoureh Karami's house looked like a typical fast food delivery bike. Her husband, nuclear scientist Masoud Alimohammadi, started his car, preparing for his usual drive to the University of Tehran.
"The moment he closed the car door I heard the sound of the explosion," Karami told VICE News. "I thought it was an earthquake."
Assassins had planted a powerful bomb in the motorcycle before detonating it by remote control, according to police investigators, killing Alimohammadi in the blast.
The January 2010 explosion was so powerful it knocked out window glass for miles, said Karami. "When I go to work through that entrance, I still feel the wave of the explosion in my mind."
Alimohammadi was one of five Iranian nuclear scientists killed in a covert war waged against Iran by Western powers and Israel, according to Iranian experts. From 2010 to 2012 Western intelligence agencies also sought to disrupt Iran's nuclear power program through targeted assassinations and by introducing a computer virus called Stuxnet into Iran's nuclear facilities.
In the Western view, an aggressive Iran seeks to create a Shia Crescent under its control, stretching from Lebanon through Syria, Iraq, and into Bahrain and Yemen.
The US, Britain, Israel, and other Western powers point at Iran providing arms to the Lebanese group Hezbollah and Syrian President Bashar al-Assad, backing Houthi rebels in Yemen, and controlling some Shia militias in Iraq.
Yet Iranians see their national security in exact opposite terms. They are the victims and the West supports terrorism. As a result of wars in Afghanistan and Iraq, the US has stationed troops in countries along Iran's borders. The US backs Saudi Arabia's aggressive actions against the Houthis in Yemen.
According to this view, the West has laid the ground work for turning Syria into a failed state. Any arms shipments or political support offered by Iran is purely in self-defense, according to Iranian officials.
And then there's the question of attacks inside Iran, such as the assassination of five nuclear scientists, including Alimohmmadi.
Iranian authorities arrested, convicted, and executed Majid Jamali Fashi for Alimohmmadi's murder. He confessed to having been trained by Mossad, Israel's version of the CIA. While Iran has coerced confessions in many cases, this admission was deemed accurate by Western intelligence officials who spoke to Time magazine.
In his confession Fashi alleged that Mossad trained him with a scale model of Alimohammadi's home in Tehran.
Israel has denied involvement in the crimes. Commentary, a neoconservative Jewish magazine, speculated that Iranian authorities may have killed the scientists because of their dissident political views. A respected Iranian-American analyst wrote that Alimohammadi may have been killed by the regime while the other scientists were murdered by Mossad.
The vast majority of Iranians, however, believe that Western governments used terrorist tactics to kill the five scientists. "The IAEA [International Atomic Energy Agency] passed on the information to Western intelligence agencies, and then at least one of them gave it to the Israelis," Seyed Mohammad Marandi told VICE News. Marandi is an assistant professor at the University of Tehran who was part of the Iranian delegation to the Vienna nuclear talks in July.
And Iran has appeared to retaliate for the murders. In 2012 Iranian agents were suspected of attempting assassinations and bombings of Israeli targets in Thailand, Azerbaijan, Singapore, and Georgia. A man on a motorcycle in New Delhi attached a sticky bomb to the car of the wife of an Israeli diplomat in what appeared to mimic similar attacks against scientists in Tehran.
Leaders in Tehran want Western powers to take Iran's national security concerns seriously. Marandi lists three key elements: independence, secure borders, and opposition to extremism as promoted by Saudi Arabia.
"If these three issues are addressed in a reasonable way, this region could be normal," he said.
Critics say Iran wants a lot more than those benign objectives. In the first years after 1979, Iran tried to spread its revolution to nearby Shia countries Iraq and Lebanon. Iran assassinated Iranian Kurdish leaders living in Germany in the 1990s. Argentine authorities accused Iran of organizing the 1994 bombing of Jewish community center in Buenos Aires. Iran denies the accusation.
And, of course, the West still sees Iran as a potential nuclear threat. Iranian leaders have always said that their enrichment of uranium was for producing nuclear power, not bombs. Iran seeks energy self sufficiency as a national security issue.
Back in the 1960s Shah Mohammad Reza's government predicted that Iran would eventually deplete its oil and natural gas reserves. With US and European backing, Iran planned to build 18 nuclear reactors. However, Western nuclear corporations pulled out of Iran after the 1979 revolution.
Marandi says Iran still faces an energy shortage and seeks to develop nuclear, hydro, wind, and solar power. "The Iranians feel they must move beyond oil and gas because they will be left behind in the years to come," he added.
Iran has one functioning nuclear reactor, Bushehr, located along the Persian Gulf coast. It was originally built by German companies in the 1970s, and more recently has been refurbished by Russia. It provides about 1.5 percent of Iran's current electricity, according to Marandi.
In the rush to develop nuclear power, there's been little discussion of its environmental and safety hazards. Western experts have warned that aging equipment and lack of safety precautions at Bushehr could cause another Chernobyl disaster.
Marandi argues that the Soviet nuclear plant in Chernobyl, which suffered a catastrophic explosion in 1986, was an old model. "The technology now used by the Russians and Chinese is very different today than it was in the past."
Unlike safety issues, the cost of Iran's nuclear program has started to generate controversy in Iran. The government has not revealed the overall costs. A RAND Corp study estimated the nuclear program cost Iran $100 billion, including the impact of sanctions.
The cost of the program is "a big discussion right now," Mehrdad Khadir told VICE News. He is chief editor of the weekly magazine Omid Javan (Hope of the Youth). "How much money did we lose over the past 10 years?"
A startling admission recently came from Abbas Araghchi, Iran's chief nuclear negotiator in Vienna. He spoke off the record to Islamic Republic of Iran Broadcasting (IRIB) recently, but his remarks were posted online before being hastily removed.
"I have always said that if we judge our nuclear program on purely economic criteria, it is a big loss — meaning that if we calculate the cost of the products, it makes no sense at all," said Araghchi. "But we paid these costs for our honor, our independence and our progress… Our program… will become cost-effective in time."
In this regard, the nuclear policy of Iran, US and other powers who negotiated the Vienna agreement bear a striking resemblance. With the exception of Germany, they all maintain or seek to expand nuclear power generation. Cost, safety, and environmental impact are of secondary concern.