The body of Tia Sharp was wrapped in a black bed sheet and hidden in a black bag, it has been reported.
The remains of the 12-year-old were found in the loft at the home of her grandmother, Christine Sharp, the Evening Standard said.
Scotland Yard would not confirm these details, although they were also reported by the Daily Mail, the BBC and the Telegraph.
It comes as Tia's step grandfather, who is accused of her murder, was remanded in custody on Monday after appearing at court.
Stuart Hazell, 37, sounded emotional as he spoke to confirm his name and date of birth.
His voice cracked when he was asked to confirm his address, The Lindens, New Addington, south London, where Tia was found dead.
Stuart Hazell has been charged with murder
Hazell appeared from Sutton police station by video link at Camberwell Green Magistrates' Court, south east London.
Hazell was dressed in a blue T-shirt and sat alone at a table with a policewoman standing behind him.
No plea was entered to the charge, which accuses him of murdering the youngster between August 2 and 11.
Her body was found on Friday, a week after she was reported missing and after a search was launched for her.
Grief: Natalie Sharp breaks down as she views tributes to her daughter
Hazell will appear at the Old Bailey on Wednesday, when there might be a bail application.
A further date for a preliminary hearing was recorded as November 19. No relatives appeared at court on Monday.
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Hazell is the partner of Tia's grandmother Christine Sharp, 46.
She was arrested on suspicion of murder but bailed yesterday pending further inquiries along with her next door neighbour Paul Meehan, 39, who was bailed on suspicion of assisting an offender.
Despite visiting the terraced property on several occasions, investigators only discovered Tia's body on Friday evening.
Tributes to the schoolgirl included candles, flowers and soft toys
Officers have apologised to Tia's mother, Natalie Sharp, for the delay in locating her body.
Yesterday the grieving mother wept as she left a tribute to her daughter alongside hundreds of flowers and cards which carpet the pavement near the 46-year-old grandmother's home.
A note believed to have been left by Ms Sharp, 30, read: "Our baby girl, we love you very much and always will.
"Sorry baby that this has happened, I wish I was there to protect you.
"We know you are safe now and you are at home with us everywhere we go. Love you, mum, dad, Jack and Harry. XXX".
A post-mortem examination on Tia's body was paused on Saturday night and is expected to recommence this week.
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