An analyst¡¯s missed remarks and U.S. intelligence systems that weren¡¯t connected to one another are among the missteps that investigators have surfaced while probing the cause of a missile strike on an Iranian school that killed an estimated 120 children, people familiar with the matter said.

Years before the U.S. attacked Iran at the end of February, an intelligence analyst examining information about potential future strike targets in Iran noticed changes at a site the U.S. had previously characterized as a naval facility belonging to the elite wing of the Iranian military in Minab city in the southeast of the country. It was, in fact, now an elementary school.

The analyst remarked on changes at the site in a digital intelligence tool, but that tool wasn¡¯t linked up to the official intelligence database that the U.S. uses to develop strike targets and the information was never conveyed to military commanders, according to people familiar with the matter who declined to be named discussing sensitive matters.