The body of 12-year-old Tia Sharp is understood to have been so badly decomposed that it had to be identified by dental records.
Police searched for the missing teenager for a week after she went missing on 3 August and eventually found her remains wrapped in a sheet and bin bags in her grandmother's loft in New Addington, Surrey.
Because of high temperatures in the loft, police reportedly struggled to identify the body. A full post mortem took place at Croydon Mortuary, where the deceased was identified, although a cause of death could not be established.
The body can be released to the family, although Stuart Hazell, partner to Tia's grandmother Christine Sharp and the man charged with the teenager's murder, can ask a second investigation.
Coroner Dr Roy Palmer said: "The accused person is entitled to ask for an autopsy conducted by the pathologist of his choice."
Hazell, 37, has been remanded in custody after a brief appearance at the Old Bailey. The defendant, 37, appeared by video link from Belmarsh prison and made no application for bail.
Christine Sharp, 46, and her neighbour Paul Meehan were held on suspicion of assisting an offender and were bailed until October.
Hazell's trial will continue on 19 November.