poor service

My sister was ****d last month she opened a case in site b police station, the detective that was in charge of the case told my sister she should call the police when ever she sees the ******, we had to do a follow up that's when the detective came to our house to enquire about the case after that nothing has been done, women are finally coming out about being ****d by the same person and his still walking freely the police are failing us dismally