More than three years after the Department of Education vowed to open a good-faith investigation into whether students at the city's ultra-Orthodox Jewish schools are receiving a proper secular education, officials now admit that they still haven't been granted access to 15 of the controversial yeshivas.

On Wednesday, New York City Schools Chancellor Richard Carranza addressed the "long delay in scheduling visits" in a 14-page letter to State Education Commissioner MaryEllen Elia, calling the lack of access a "serious concern" and requesting further guidance. According to the letter, DOE investigators have conducted pre-scheduled visits to 15 elementary schools, where they observed that around a third of classes were focused on biblical studies and taught in Yiddish, Hebrew, or Aramaic. A majority of the yeshivas were using an updated curriculum for math and English provided by the pro-yeshiva group Parents for Educational and Religious Liberty in Schools [PEARLS], the letter noted.

Those preliminary findings follow allegations made in 2015 by a group of yeshiva alumni, parents, and former teachers, who say students receive only 90 minutes of English and math instruction just four days a week. State law requires that education in private schools, including yeshivas, must be "at least substantially equivalent" to what's provided in public schools.

In response to the letter, Young Adults For A Fair Education—an advocacy organization led by Orthodox community members who want secular reforms at the yeshivas—called the schools' refusal to grant access "disappointing, but not surprising."

"Reading between the lines it's hard not to conclude there is both a lack of secular instruction going on in these schools and that these schools believe they are above the law," said Naftuli Moster, the executive director of Yaffed. "But, we are also disappointed that the DOE conducted announced visits. Undoubtedly, the schools prepared for those visits and put their best foot forward—even if it was a fabricated foot. I have no doubt that what the DOE saw on their visit is not exactly what happens in those schools the other 364 days of the year."

The group, which has long-criticized the slow pace of the investigation, released a report last year highlighting the shortcomings of a yeshiva education, noting that "young men lack the requisite skills to obtain employment with a decent income to support themselves and their (often large) families." Last month, the group filed a lawsuit against the recently-passed Simcha Felder Amendment, which they say will serve to exempt yeshivas from the state law requiring substantial equivalency.

PEARLS, meanwhile, released their own statement to Yeshiva World about the letter, which they say "confirms that Yaffed's allegations against the yeshivas have no basis in fact." The group also called for an end to the investigation, and claimed that "any suggestion that the yeshivas were less than cooperative in arranging the remaining visits is false."

While legislation governing New York's yeshivas is made in Albany, oversight of those laws has typically fallen to local districts. Last spring, however, State Education Commissioner Elia took charge of evaluating whether private schools are providing substantial education to their students. The commissioner is expected to release new guidelines for determining whether those schools are complying with the law in the coming months.

On Thursday morning, Carranza affirmed that the probe would continue, while nodding to the forthcoming direction expected from state. "We deeply believe that all students—regardless of where they attend school—deserve a high-quality education," he said. "We will ensure appropriate follow up action is taken based on guidance provided by SED."