The girl, identified as only N, was kidnapped from her school in Azizabad on September 24 and her body was found by the police today near the Beach View Club here.
"The girl was raped and than murdered but there are bruises all over her body. We are still not sure if more than one person raped her," an official at Jinnah hospital said.
SSP central, Aamir Farooqi said the police were investigating the case but had not got any solid leads.
The girl had told her classmates before being taken away that she was going home early.
"That indicates she was not kidnapped for ransom," Farooqi said.
The girl's parents lodged an FIR with the police in connection with her kidnapping on the same day she went missing.
Her parents told a television channel they had also received threats.
Police said the girl's class teacher, relatives and the school's principal are being questioned and the gatekeeper of the school had been taken into custody.
