At some of New York City’s yeshivas, attendance was voluntary when it came time to learn secular subjects like math and English. Students said they didn’t learn math beyond basic division and fractions. None of the students reported receiving steady lessons in science. 

That’s according to a long-delayed probe by the New York City education department into whether some of the city’s private Jewish schools are providing an adequate secular education for students. But even as the city released findings on Thursday, it admitted that it was never able to go inside any high schools and never received a full set of curriculum materials to evaluate — significant gaps for a report that took three years to be released.

In a letter sent to the state education commissioner on Aug. 15, schools Chancellor Richard Carranza asked the state for guidance on how to proceed after a recent change in law that put the state education commissioner in charge of evaluating the schools. The Wall Street Journal first reported on the letter. 

“We deeply believe that all students — regardless of where they attend school — deserve a high-quality education. We will ensure appropriate follow up action is taken based on guidance provided,” Carranza said in a statement.

The letter marks a new phase of an investigation sparked by current and former students and parents who complained they received little instruction in math or English while attending the schools. The city has been accused of delaying the investigation to avoid angering a politically powerful community.

New York requires private schools to provide instruction that is “substantially equivalent” to public schools, and that allows the schools to access public money for things like school security. Students and parents who were interviewed for the probe said they received instruction in math and English for only 90 minutes for four days out of the week, and all but two said they received “little to no” history lessons, according to the city’s letter.

The report finds that some schools have adopted new curriculums in English and math, but officials have not been able to evaluate the new materials because they haven’t received a complete set.

The city also said that officials at eight of the schools they were unable to visit recently gave word that they would schedule meetings.

Read Carranza’s full letter here.