The attack on a girls’ elementary school in the Iranian town of Minab was one of the US military’s deadliest civilian bombings in decades. But nearly four months on, the Pentagon has produced no answers about why the military fired a Tomahawk cruise missile into a school on the first day of the war, killing at least 175 people, mostly children.

Some critics doubt that the Pentagon ever will, or will bury the results under classifications to keep the worst mistakes secret from the public.

As the US signs a shaky memorandum of understanding on a ceasefire with Iran, the secretive investigation into the attack has also become a test case for the self-styled secretary of war Pete Hegseth’s new approach to what he calls “warfighting”. As he said in early March, nearly two weeks after the attack, “our rules of engagement are bold, precise and designed to unleash American power, not shackle it”.