A schoolboy who murdered his former girlfriend after she ended their relationship cleaned the scene before heading to school, Bristol Crown Court heard today.
Thomas Griffiths, now 18, stabbed Ellie Gould to death in Calne in Wiltshire, on May 3.
He pleaded guilty to murdering her at a previous hearing and will be sentenced at Bristol Crown Court later today. Mr Justice Garnham will sentence Griffiths of Derry Hill, Wiltshire.
Griffiths had told the court he and Ellie began to revise but Mr Smith said no revision folders were left out when her body was later discovered.
"Griffiths became angry, perhaps by Ellie's continued rejection of him and he attacked her," Mr Smith said. "A post-mortem examination indicated that Ellie was first incapacitated by pressure having been applied to her neck.
"Thereafter, multiple knife wounds were inflicted. There are at least 13 wounds inflicted, with the knife focused mainly around the area of the left neck. The knife that was used to kill Ellie was one that was taken from the family kitchen."
Mr Smith said Griffiths had attempted to clean up the murder scene with cloths he later hid in a wood near his home. Blood-staining on an apron suggests Griffiths wiped the knife before placing it back in Ellie's neck.
"The defendant must have placed his victim's own hand on the handle of the knife," Mr Smith said. "No doubt to make it look as though she, Ellie, had inflicted the wounds on herself."
At 11.45am, a text was sent from Ellie's phone telling a friend that she was not going to school that day.
After the murder, Griffiths drove home and told a neighbour he had self-harmed, with deep scratches to his neck.
"In truth, the injuries to the defendant's neck and to his hand were nothing to do with self-infliction but very much more likely the product of his young victim having fought for her life as she was attacked," Mr Smith said.
Griffiths then asked his neighbour to drive him to school, where he spoke to the matron and sent messages to Ellie's phone. He was collected from school from his mother, who later took him to a friend's house in Chippenham.
At 3pm, Ellie's father Matthew Gould returned home to find his daughter lying "face down in a pool of blood, with the knife in her neck," Mr Smith said.
Griffiths was arrested outside his friend's home at 6pm.
In a victim personal statement, Mr Gould said: "The image of Ellie lying there on the floor has haunted me ever since that afternoon.
"It fills my thoughts when trying to sleep and hijacks my mind when trying to go about my day."