The Education Department (ED) has concluded its investigation at Princeton University, determining the Ivy League institution violated the Title IX gender equity law in its handling of sexual assault cases.

According to the Huffington Post, the ED's Office for Civil Rights (OCR) had been investigating Princeton for four years. Announcing the conclusion of the investigation Wednesday, the OCR concluded that the school's handling of various sexual assault cases improperly favored the accused.

As part of a resolution agreement reached with Princeton, the school will have to adopt several policy changes and reimburse three students who were wronged in their sexual assault complaints for part of their tuition.

"In response to the above-referenced complaint, OCR examined whether the University responded promptly and equitably to complaints, reports, and any other notice to the University of incidents of sexual harassment, sexual assault and other forms of sexual violence, including the students' reports of sexual assaults; and whether as a result, students, including the students at issue in the above-referenced complaints, were subjected to a sexually hostile environment," the OCR wrote in a notification letter to Princeton on Wednesday.

Title IX is federal law prohibiting gender bias and discrimination. The OCR cited an unreasonably high burden of proof as one way Princeton violated the rights of the complainant. The school also allowed several privileges to the accused during the disciplinary process that the complainant did not receive.

"I applaud Princeton University for its commitment to ensuring a community-wide culture of prevention, support, and safety for its students, staff, and community," Catherine Lhamon, ED assistant secretary for civil rights, said in a statement. "We look forward to continuing to work cooperatively with Princeton to implement this agreement."

Princeton adopted a new sexual misconduct policy last year amid the federal investigation and the school will now have to prove how they have improved their practices in upholding it.

"We are pleased that this investigation has been concluded with an agreement that brings the University's policies and procedures into compliance with all statutory and regulatory requirements," Christopher L. Eisgruber, Princeton's president, said in a statement. "The agreement reaffirms our commitment to address all matters of sexual misconduct in ways that are fair, effective, and transparent, and our determination to ensure a campus climate that places high priority on prevention and support, and on ensuring safety and freedom from discrimination for all members of our campus community."