Last July, Iran’s center for advanced nuclear centrifuges was left in smoking ruins after an explosion that Iranian officials tried their best to cover up for months. But, last week, in an interview on Iranian state television, the country’s former nuclear chief came clean about how badly the July 2 blast hit the Natanz nuclear facility—and the old-school Bondlike method used to plant the bomb. According to Fereydoon Abbasi-Davani, the ex-head of Iran’s Atomic Energy Organization, the explosives were hidden and sealed inside a “heavy desk” that had been planted in the facility several months earlier. He told state TV the bombers “amended the explosive [in the desk] and sealed it, using, perhaps, resin or welding the steel” before they snuck it past security workers. That explosion set Iran’s nuclear enrichment program back by months, officials said at the time. Another explosion at Natanz on April 11 set it back further.