Police recovered the body of an eight-year-old school child from a septic tank in Gazipur city on Sunday night.The victim was a second grade student at Hyderabad Government Primary School.Family members alleged that the victim was raped before murder, said Sub-Inspector (SI) Mobarak Hossain of Pubail police camp.Her body has been found in the septic tank of the house of one Rahmat Ullah, 18, cousin of the victim in Dakhinkhan Purbapara area around 11pm.The body has been sent to morgue.A case was filed in this connection accusing Rahmat Ullah Mona, 18, his mother Fojilot Begum, 40, and his sister Nasima Akhter.Police arrested Fojilot Begum and Nasima Akhter from their residence while Rahmat is on the run.