The 15-year-old, who cannot be named for legal reasons, committed the unprovoked assault in the early hours of 22 September last year in the woman’s bedroom in their family home.
He dialled 999 immediately afterwards to report that he had committed ‘an attempted murder’ and later told police officers: ‘I don’t know why I did it.’
The boy was sentenced on Monday to two years and nine months’ youth detention by the Superior Number of the Royal Court, which only convenes for the most serious cases, after pleading guilty to grave and criminal assault.
Outlining the case for the prosecution, Crown Advocate Conrad Yates said: ‘It was premeditated because he texted, he got dressed and went down to the kitchen to get the knife. Evidence shows that there was no provocation, so it was committed in cold blood. The blows were sufficient so she would need stitches and not glue to her injuries. And the emotional impact cannot be underestimated – she wants to leave Jersey and cannot live with her brother.’
Advocate Lauren Glynn, defending, said that the attack was an ‘isolated incident’ and asked for the defendant’s young age and lack of previous convictions to be considered.
She added that a psychiatric report said that a recent Shapchat exchange with a girl may have triggered an ‘acute stress reaction’ in the defendant.
