According to a police report on Sunday, PC Francis Makau was standing guard on Saturday night when he left the report office and released one Mercy Mulei, 32, and committed the alleged crime in one of the office rooms based in the station.
Makau is said to have made his move after his colleague PC Ali Abdi had gone to answer a nature call.
Upon arriving at the report office she did not see Makau but heard two people conversing inside one of the rooms.
“She pushed the door where she found them dressing up and attacked the prisoner (Mulei) using a heavy stick where she sustained head injuries and suspected fracture on her left femur,” read the report.
Mulei was rushed to Mutitu Sub-County hospital for treatment and examination.
Meanwhile, PC Makau is being held in custody for the offence of rape and his wife for assault.