In just six months last year, the Department of Justice fielded over 450 complaints from individuals who alleged that their civil rights or civil liberties were abused by law enforcement officers, but the vast majority of those complaints went unanswered by its Inspector General.

Of the trio of those that the department determined worthy of an investigation, according to an IG report released Monday, all three were brought by Muslims, who said they were discriminated against by the criminal justice system.

Two of the investigations are focused on the Bureau of Prions (BOP) and concerns inmates who say correctional officers mistreated them because of their faith.

In one case, “A BOP inmate alleged that, during a search of his cell, two correctional officers assaulted him, used a racial slur, and made a derogatory statement against Muslims.”

Another BOP inmate alleged that he was subject to abuse during the high holy month of Ramadan, in which “two correctional officers intentionally delivered his breakfast two hours late, made derogatory comments against Muslims, threw milk on him, and destroyed his property, including Islamic literature.”

A third investigation concerns the FBI and the DEA. A complainant alleged the agencies “racially profiled and targeted for investigation both himself and other individuals at an Islamic center.” He said authorities claimed the investigation was related to drug offenses, but that he and others were “repeatedly questioned” about their national origin and ties to Pakistan.

That complaint is reminiscent of a story published last July by The Intercept, which revealed how the National Security Agency and the FBI “covertly monitored the emails” of five politically-active Muslim-Americans “under secretive procedures intended to target terrorists and foreign spies.”

The IG report also touched on other investigations opened during previous reporting periods that have not yet been closed. Those, too, are related to Muslim inmates suffering abuse at the hands of prison guards.

In one instance, “A Muslim inmate alleged…that he suffered physical abuse when an unidentified officer assaulted him while he was in full restraints.” Another complaint concerned a BOP chaplain who denied the alleged victim and other Muslim inmates, “basic rights in violation of BOP policy, such as being able to pray at job sites and participating in religious rituals.”

The odds that these complaints result in discipline for DOJ employees are long. Four investigations were completed during the current reporting period, all of which also concerned Muslim inmates at US prisons. In all of those cases, neither the IG nor the Bureau of Prisons determined the allegations were substantiated, and they closed their investigations.

The accounting detailed Tuesday is mandated by a section of the 2001 PATRIOT Act.

Ninety-percent of complaints received in the last reporting period of 2014 did not “warrant further review” from the IG. The majority of those originated from agencies outside the watchdog’s jurisdiction—including Department of Homeland Security organs like the Transportation Security Administration and Customs and Border Patrol.

The IG said that complaints are referred to the appropriate entity outside the DOJ “when possible,” but noted that it cannot deal with all matters that it could be overseeing itself.

“Given the number of complaints the [inspector general] receives compared to its limited resources, the [IG] does not investigate all allegations of misconduct against DOJ employees,” the report noted. The investigation stated that, in many cases, complaints are referred to multiple agencies within the department, including the FBI Inspection Division, the Drug Enforcement Agency (DEA) Office of Professional Responsibility, and the Bureau of Prisons Office of Internal Affairs.

All in all, the IG counted 458 civil rights or civil liberties complaints in the last six months of 2014. Read the full report here.