A girl was buried alive by relatives in a gruesome honour killing just because she reportedly befriended boys. Source: AFP

Acting on a tip-off, police discovered Medine Memi's body in a sitting position with her hands tied, in a two-metre deep hole in a chicken pen outside her house in Kahta town, Adiyaman province, 40 days after she went missing, the agency said.

A subsequent post mortem revealed that she had a significant amount of soil in her lungs and stomach, meaning that she was buried alive, forensic experts told the agency.

"The autopsy result is blood-curdling. According to our findings, the girl, who had no bruises on her body and no sign of narcotics or poison in her blood, was alive and fully conscious when she was buried," one anonymous expert said.

Medine's father and grandfather have been formally arrested and jailed pending trial over her killing, the agency said.

The father is reported to have said in his testimony that the family was unhappy she had male friends.

In honour killings, most prevalent in Turkey's mainly Kurdish southeast, a so-called family council names a member to murder a female relative considered to have sullied the family honour, usually by engaging in an extra-marital affair.

But the practice has gone so far as to kill rape victims or women who simply talked to strange men.