TThe assassination of Iranian Supreme Leader Ayatollah Khamenei was the culmination of decades of painstaking intelligence gathering by Israel’s secret services, with the CIA and other U.S. intelligence agencies providing critical technical and human resources over the past six months, culminating in a deadly eruption of violence that decapitated the Iranian regime, Israeli and U.S. experts, veteran spies and officials said.

Israeli military officials said Khamenei was killed within 60 seconds in near-simultaneous attacks along with seven “members of Iran’s security leadership who had gathered in several locations in Tehran” and about 12 members of his family and aides. Forty other senior Iranian leaders were also killed in the attack.

The killing of Khamenei, 86, marked the beginning of an air force launched this weekend by Israel and the United States aimed at overthrowing the radical clerical regime in Tehran, plunging the Middle East into fresh chaos and violence.

But some experts and intelligence veterans cited the potential for strategic mistakes that could alienate potential supporters or pave the way for more radical opponents in the future.

“The problem is that Israel is obsessed with assassinations…and we never learn that that’s not the solution. We killed all the leaders of Hamas. They’re still there. Same with Hezbollah. Leaders change all the time,” said Yossi Melman, a respected Israeli analyst and intelligence author.

Israel has a long history of assassinations abroad, but it has never killed a head of state.

Amos Yadlin, former head of Israel’s military intelligence, said the attack was a “tactical surprise, operational surprise” as the public expected Israel to strike in the dark and repeat the surprise attack that started the 12-day war in June.

The timing of the assassination was determined by information gathered by the CIA about a meeting of Iranian government officials at a leadership complex in central Tehran scheduled for Saturday morning. Most importantly, the CIA was able to inform the Israelis that Khamenei would be on the scene and the timing of the meeting, according to the New York Times.

Israeli spies had also been following Khamenei for years, building detailed files on his daily life and the daily lives of his family, colleagues, allies and those he was responsible for protecting.

“It’s like a giant jigsaw puzzle. You’re putting all the pieces of information together. Where are the missing pieces? [reliable data] You examine them further. It’ll be everything: how do they get their food, what happens to their trash…we all wake up and go to sleep, eat and drink,” said the former CIA veteran with decades of experience tracking high-profile terrorist targets.

“We live in a world that is so layered with information and data. There’s no one who doesn’t leave a trace in some way. Everything you do leaves a trace.”

Royel Gerecht, a former CIA targeting official and analyst for Iran and the Foundation for Defense of Democracies, said that although Israel built a network of ground agents who could provide human intelligence and carry out covert operations inside Iran, the United States could have leveraged significant technological assets.

Gerecht said Israeli media reports that photos of Khamenei’s remains were shown to Donald Trump and Israeli Prime Minister Benjamin Netanyahu were plausible.

“The U.S. has very good technology, and that technology is very important, but I don’t think the U.S. has very good technology. [CIA] had a lot to bring to the table regarding [human intelligence] Or a covert action network,” he said.

“The combination of technical capabilities and terrestrial networks will certainly amplify the impact.”

Mossad, short for the Institute for Intelligence and Special Operations in Hebrew, has focused on Iran for decades, building a deep network of Iranian informants, operatives and logistics. This allows the following sequence of operations. Assassination with remote controlled automatic machine gun Iran’s top nuclear scientist was driven down a remote road at breakneck speeds, computers running key parts of Iran’s nuclear program were infected with malware, and archives of nuclear documents were stolen. Ismail Haniyeh, the political leader of Hamas, In 2024, he will be assassinated by planting a bomb in his favorite room. At the Government Guest House in Tehran.

During the 12-day war in June, Israeli operatives were able to locate the homes of Iranian nuclear scientists, intelligence officials, and military commanders, information that led to dozens of people being killed in the first wave of surprise attacks.

Melman said Mossad made a significant change in strategy nearly 20 years ago, deciding to employ local operatives inside Iran who were given state-of-the-art equipment and advanced training.

David Balnea, who has led Mossad since 2021, has created a special division for a “foreign corps” of agents sent across the Middle East on sensitive missions.

Mehlman said it was easier to recruit such agents in Iran, where the country’s population is largely opposed to the ruling regime, than in other parts of the country.

Israel was poised to assassinate Khamenei last year, but President Trump was reluctant to risk the reaction of allies concerned about regional escalation and the killing of the head of state. Those reservations appear to have evaporated in the months since last year’s brief conflict, which ended shortly after U.S. bombers struck Iran’s nuclear facilities.

Israeli military officials said there has since been “very enhanced cooperation” between Israel and the United States regarding Iran.

The flow of information from Mossad’s network on the ground in Iran would have been integrated with information gathered through communications intercepted by the United States last week.

“I wouldn’t be surprised if they went to different lengths to track us down.” [Khamenei]”Iranians are pretty sloppy. They love cell phones. So maybe the Supreme Leader had a ton of phones, but it was about people he was calling regularly.”

Finally, the information would have been provided to the US and Israeli militaries, allowing accurate targeting information to be gathered and orders to be issued in that brief but deadly and destructive moment.

“Sixty seconds. That’s how long this operation took, but it was the result of years of preparation,” said Oded Ayram, former head of Mossad’s counterterrorism division and a researcher at the Jerusalem Center for Security and Diplomacy. “The modern battlefield is no longer defined only by tanks and aircraft; it is defined by data, access, trust, and timing. A minute can change a region.”

The CIA veteran said he believed the assassination was a mistake, saying, “I think it was a mistake. Not from an ethical point of view, because I was fine with killing people, and I have killed many people, but from a long-term strategic point of view.”

“We know that removing someone’s leader won’t solve the problem; it will only create new problems.”