KANSAS CITY, Mo. (AP) — The Kansas City, Missouri, Fire Department is under a U.S. Department of Justice investigation for alleged racial discrimination, a Kansas City spokesperson confirmed to The Kansas City Star Thursday.

Associated Press phone calls requesting comment from the federal agency were not immediately returned Thursday.

Three Black firefighters told the newspaper that they were interviewed by the Department of Justice within the past year about racism and their treatment at the agency. A Black firefighter sued last week, claiming he was retaliated against for talking to the Justice Department, the newspaper reported.

The federal investigation comes after The Kansas City Star reported on unwritten rules within the department that kept Black firefighters from preferred stations, hampered their ability to be promoted and often left them ostracized in majority-white stations.

In one incident, a white fire cadet “joked” that his favorite knot was a noose and placed it around the neck of Black classmate at the fire academy two years ago. The city tried to fire him, but he resigned after intervention from the firefighters union.

The paper reported that only 14% of fire department employees are Black, in a city where 30% of residents are Black. Its stations remain unofficially segregated by longstanding promotion practices. At some busy inner-city fire stations, there hasn’t been a Black captain in at least a decade.

Female firefighters also reported severe sexual harassment.