Israel’s broadened focus on Hizbollah in the region was accompanied by a growing, and eventually insurmountable technical advantage — spy satellites, sophisticated drones and cyber-hacking capabilities that turn mobile phones into listening devices.

It collects so much data that it has a dedicated group, Unit 9900, which writes algorithms that sift through terabytes of visual images to find the slightest changes, hoping to identify an improvised explosive device by a roadside, a vent over a tunnel or the sudden addition of a concrete reinforcement, hinting at a bunker.

Once a Hizbollah operative is identified, his daily patterns of movements are fed into a vast database of information, siphoned off from devices that could include his wife’s cell phone, his smart car’s odometer, or his location. These can be identified from sources as disparate as a drone flying overhead, from a hacked CCTV camera feed that he happens to pass by and even from his voice captured on the microphone of a modern TV’s remote control, according to several Israeli officials.

Any break from that routine becomes an alert for an intelligence officer to sift through, a technique that allowed Israel to identify the mid-level commanders of the anti-tank squads of two or three fighters that have harassed IDF troops from across the border. At one point, Israel monitored the schedules of individual commanders to see if they had suddenly been recalled in anticipation of an attack, one of the officials said.

But each one of these processes required time and patience to develop. Over years, Israeli intelligence was able to populate such a vast target bank that in the first three days of its air campaign, its warplanes tried to take out at least 3,000 suspected Hizbollah targets, according to the IDF’s public statements.

“Israel had a lot of capabilities, a lot of intelligence stored waiting to be used,” said a former official. “We could have used these capabilities way longer ago during this war, but we didn’t.”

That patience appears to have paid off for the military. For more than 10 months, Israel and Hizbollah traded cross-border fire, while Israel killed a few hundred of Hizbollah’s low-level operatives, the vast majority of them within a slowly expanding theatre of the conflict, stretching a few kilometres north of the border.

That appears to have lulled Nasrallah into thinking that the two arch-rivals were involved in a new sort of brinkmanship, with well-defined red lines that could be managed until Israel agreed a ceasefire in Gaza with Hamas, allowing Hizbollah an “off-ramp” that would allow it to agree a ceasefire with Israel.

The group had only started this round of fire with Israel on October 8, in solidarity with Iran-backed Hamas, in an attempt to keep at least some Israeli firepower pinned down on its northern border.

“Hizbollah felt obliged to take part in the fight, but at the same time limited itself severely — there was never really any intention of them taking an initiative where they might have some advantage,” said Sayigh of the Carnegie Middle East Center.

“They seem to have thrown off a few rockets here and there, and taken a few hits in return, and getting lulled into a notion that this was the limit of it — they kept one, if not both, hands tied behind their back and did nothing approaching their own full capability.”

in recent months, if not years, Israeli intelligence had nearly perfected a technique that allowed it to, at least intermittently, locate Nasrallah, who had been suspected of mostly been living underground in a warren of tunnels and bunkers.

In the days after October 7, Israeli warplanes took off with instructions to bomb a location where Nasrallah had been located by Israel’s intelligence directorate Aman. The raid was called off after the White House demanded Netanyahu do so, according to one of the Israeli officials.

On Friday, Israeli intelligence appears to have pinpointed his location again — heading into what the IDF called “a command and control” bunker, apparently to a meeting that included several senior Hizbollah leaders and a senior Iranian commander of Revolutionary Guards operations.

In New York, Netanyahu was informed on the sidelines of his address at the UN General Assembly, where he rejected the notion of a ceasefire with Hizbollah and vowed to press on with Israel’s offensive. A person familiar with the events said that Netanyahu knew of the operation to kill Nasrallah before he delivered his speech.

Israel’s campaign is not over, says Netanyahu. It is still possible that Israel will send ground troops into southern Lebanon to help clear a buffer zone north of its border. Much of Hizbollah’s missile capability remains intact.