A woman has described to a jury how her former boyfriend began to panic after realising that he had killed a 15-year-old boy.
Nicolette Vaux-Phillips, 19, was giving evidence at the Christchurch High Court at the trial of her former partner Gavin Gosnell.
The 28-year-old is accused of beating Hayden Miles to death on 22 August in 2011 and later dismembering his body and burying it in two graveyards in central Christchurch.
On Monday, Gavin Gosnell denied the charge of murder at the beginning of his trial. However, his lawyer Craig Ruane said the accused did not deny killing the boy and the jury must decide whether he is guilty of murder or manslaughter.
Ms Vaux-Phillips told the court on Tuesday that the morning after the prolonged and violent assault she realised that Hayden had died of his injuries.
The 19-year-old said when friends came over to the flat in Cashel Street, Mr Gosnell asked them what he should do. She told Mr Ruane that the accused started to panic and locked the house so she couldn't leave.
Ms Vaux-Phillips told the court that Mr Gosnell began to try and dismember Hayden Miles's body with a knife and a gib saw.
She said the accused brought the body parts into their bedroom where she was and packed them into a rubbish bag before the pair later disposed of them in two cemeteries in central Christchurch.
Ms Vaux-Phillips described how they then cleaned the house, removed the carpet and burnt it in the backyard before she caught a bus to Dunedin.
Also giving evidence on Tuesday was a witness who knew Gavin Gosnell and who has name suppression.
The witness used to live next door to the accused and told the court that, when drinking together one night, Mr Gosnell asked if he had been in the same room as someone who had killed a person.
The witness replied that he had been in jail and that yes, he had. He said Mr Gosnell laughed at his response.
Mother tells of communication with friend
In a statement read out to the court on Tuesday, the mother of Hayden Miles described the many communications she had with Nicolette Vaux-Phillips, who already knew that he was dead.
Mrs Miles described Facebook messages posted by Ms Vaux-Phillips.
"I had been checking Hayden's Facebook page regularly. I noted a message posted by Nicolette Vaux-Phillips on Hayden's Facebook page on 23 August 2011 that read: 'What you up to - I hope you got home safe'".
Mrs Miles said she began a series of Facebook messages with Ms Vaux-Phillips, who repeatedly said that she hadn't seen Hayden and didn't know where he was.