The body of 13-year-old Claire Hart was then thrown into a fast-flowing river near her home. Craig Smith, 20, of Buglawton near Congleton, denies murdering Claire on 18 June last year.

Patrick Harrington QC, prosecuting, said the murder was "brutal, senseless and without any motive the prosecution have been able to discern".

Claire had been walking the mile from her home in Eaton to Dane Valley High School along a footpath on the A536 road between Macclesfield and Congleton when she met Mr Smith, Chester Crown Court was told.

"Within minutes and within not many yards of their meeting the defendant beat her, shot her with an air rifle and strangled her to death," said Mr Harrington.

"He then tried to dispose of the child's body by throwing it into the fast-flowing River Dane. Sadly, it would not be discovered for a period of five days."

After the murder, Mr Smith returned home within half an hour and behaved for the rest of the day as if nothing extraordinary had happened.

'Living out prophecy'

But he gave some clues as to what he had done by showing a "preoccupation" with going back to the scene, where he was seen at least twice during the afternoon, said Mr Harrington.

"You will hear evidence, but in a sense what the defendant was doing was living out a prophecy, something he had discussed with his parents five days before," he told the jury.

Mr Harrington said: "On Saturday, 13 June - his own mother's birthday - he told his parents that he had heard a rumour that he had killed a young girl. There was no such rumour.

"This was the wakenings in his mind, as he voiced them to his parents, of the awful thing he was going to do within a week."

'Obvious loner'

Claire had been neither physically nor emotionally mature, but was a friendly girl who trusted people.

The court heard Mr Smith was an "obvious loner" with few friends of his own age. He spent time with children years younger than himself because, as he told police, he felt "out of it".

Claire and her younger sister had been taken into care, and she was living with her prospective adoptive parents, said Mr Harrington.

"There is an ironic tragedy that the victim of this killing was a young girl who had a disadvantaged start in life, but by the care of the most caring people, she had reached a threshold where her future looked much better than her past," he said.