The Department of Investigation, which looks into misconduct in city agencies, said it couldn’t determine whether Mayor de Blasio had personally authorized the delay, and it did not allege that the mayor had violated the law. But it concluded that the administration had interfered with the Education Department’s investigation into the yeshivas. And the Department of Investigation said the mayor “personally participated in conversations with at least one state senator and Orthodox community leaders about their broader concerns regarding oversight of yeshivas and how those concerns related to the extension of mayoral control.” The local and state officials involved were not named.

While the mayor dithered, children suffered. Years passed before city school investigators saw the insides of the classrooms where former students, teachers and parents said children weren’t learning basic skills.

Yeshiva officials were treated with kid gloves, allowed to put off visits by investigators even as some former students said they graduated unable to write their names.

The conclusions of the new report are careful, and narrowly drawn.

The agencies said the 2017 agreement to delay the release of the interim report had “little to no substantive effect” on the progress of the inquiry or its conclusions. They found no criminal wrongdoing. And they cited other reasons for the delays in the city’s investigation into the yeshivas, like a change in state regulations over how to evaluate nonpublic schools, and what they called an “accommodating approach” to conflicts with the yeshivas.

De Blasio administration officials dismissed the Department of Investigation findings. “There’s no ‘there’ there,” a mayoral spokeswoman, Freddi Goldstein, said in a statement, noting that the delayed interim report wasn’t ready for release in 2017. According to the Department of Investigation, the report was held back because the city had managed to visit only six of the schools at that point — hardly a reassuring defense.