A jury sitting at Sheffield Crown Court has found Hannah Bonser guilty of the murder of 13-year-old Casey Kearney.
Casey Kearney was found fatally injured in Elmfield Park, Doncaster, South Yorkshire, in February.
The trial of Hannah Bonser who's accused of murdering 13-year-old Casey Lyanne Kearney has begun at Sheffield Crown Court.
Around ten members of Casey Lyanne Kearney's family are in court listening to the prosecution opening the case.
The prosecution say Hannah Bonser bought two knives then later went to park where she crossed paths with Casey.
They say it was then that she stabbed her and carried on walking.
The attack on Casey was sudden. No warning, no argument and no screams were heard.
The jury are hearing that after she'd been stabbed Casey managed to call 999.