Following allegations of a stabbing at Ysgol Dyffryn Aman in Ammanford, Carmarthenshire, on April 24, police were summoned. Teachers Fiona Elias and Liz Hopkin, together with a student, were treated in the hospital.
The child was on trial at Swansea Crown Court, where she denied three counts of attempted murder.
The jury was dismissed by the judge on Wednesday morning, citing a “great irregularity” that had “irretrievably compromised” the jury’s ability to deliberate the case.
Declaring that he was leaving the jury with “the greatest possible reluctance,” he remarked.
Judge Paul Thomas congratulated the jurors upon dismissing them for it.