The man, who went by “James Bond” on a messaging app, boasted to an associate last September that he had “something good lined up.”

It was an offer of easy money from the man, a 32-year-old Australian who appeared to enjoy flashy accessories like a pink Gucci cap and a diamond-ringed Rolex. Even a 16-year-old could do the job, he would later say. Torch a business near Bondi Beach in Sydney and pocket 4,000 Australian dollars, about $2,500.

A few days later, in October, a family-owned kosher eatery that had stood as a neighborhood stalwart for more than half a century went up in flames in the middle of the night.

The arson was the beginning of months of antisemitic attacks in Australia’s two biggest cities that left the nation’s Jews, who represent roughly half a percent of its population, on edge. The full picture of what was behind the attacks on Jewish businesses and institutions had largely remained unclear.

But on Tuesday, Australia’s top officials made a stunning announcement. The attack on the restaurant, they said, was actually carried out at the behest of a faraway power: Iran’s military.

Calling the operation an extraordinary attempt at undermining Australia’s social cohesion by targeting Jewish institutions, Prime Minister Anthony Albanese cut off diplomatic ties with Iran and expelled its ambassador and three other diplomats.