LOGAN, Utah (AP) — Utah State University is under investigation by the U.S. Department of Justice, an unusual step that comes after a string of sexual assault cases, school officials have confirmed.

Federal officials' investigation into the school is more serious than those going on at hundreds of other colleges across the country, said S. Daniel Carter, president of Safety Advisors for Educational Campuses LLC.

The Utah Statesman, the university's student-run newspaper, first reported about the Title IX compliance review on Monday.

Three of the university's students were charged or convicted in high-profile sexual assaults from 2013 and 2015. Among them is former football player Torrey Green.

In 2015, four women told Logan police that Green assaulted them, but no charges were filed and Green was not questioned about two of the four claims. It was only after newspapers reported and additional woman accused Green of assault that he was charged with seven assaults. Green has denied all of the allegations.

The university acknowledged that it "fell short" in handling reports related to him.

In May, former Utah State student and fraternity member Jason Relopez was sentenced to an additional 12 months in jail and ordered to complete sex offender treatment after he admitted to raping two women.

The Justice Department's Educational Opportunities Section in January opened the review into the university and its Title IX practices. Title IX is a federal law that charges universities with ensuring students receive education without sex-based discrimination.

University spokesman Eric Warren said the university is cooperating fully with the review and welcomes the opportunity to improve its process.

The U.S. Department of Education has more than 300 Title IX reviews underway nationwide, but there are few Title IX investigations by Justice Department officials, Carter said.

"This would be the only one under investigation that I am currently aware of," he said. "It is much more rare and far, far more serious."