A former Chattanooga police officer is under federal investigation by the FBI.

Officer Desmond Logan is accused of raping three women in his custody while on duty, according to papers filed in a federal lawsuit Monday. Logan was also fired in 2016 from his part-time job with the University of Tennessee, where a woman accused him of harassment. The four women all said they notified Chattanooga police.

According to published reports, an investigation into Logan wasn’t opened until one of the women reported the rape to the Hamilton County Sheriff’s Office. At the time, the police chief denied Logan had a history of complaints against him; but the lawsuit suggests the opposite is true.

Records show the Chattanooga Police Department placed Logan on leave in February; he resigned before he could be fired.