Judges hearing the case against Kenyan President Uhuru Kenyatta at the International Criminal Court have sharply rebuked prosecutors for failing to disclose evidence that could be used in his defence, but stopped short of restarting the trial.
While the reprimand will have no impact on the trial itself, it is a fresh blow to prosecutors who accuse Kenya's newly-elected president of orchestrating bloody post-election clashes five years ago in which 1,200 people died.
Judges said prosecutors should have told defence lawyers a crucial witness was not present at a meeting where prosecutors alleged acts of violence were planned, saying the prosecution made a "grave mistake" in not doing so.
The loss of that witness's testimony contributed to the acquittal earlier this year of civil servant Francis Muthaura, Kenyatta's co-accused. Similar charges still stand against Kenyan deputy president William Ruto.
But judges said there was no evidence prosecutors had deliberately withheld the exculpatory evidence, and turned down defence demands that the trial be abandoned or taken back to the confirmation of charges stage, when judges decide if the prosecution's case is strong enough to warrant a trial.
One judge went further in her criticism of the prosecutors.
In a separate opinion, Christine van den Wyngaert said it was clear prosecutors were "not even remotely ready" when the trial had begun.
"By the extremely late and piecemeal disclosure of an inordinate amount of totally new evidence, which was the immediate consequence of the prosecution's failure to investigate properly prior to confirmation, the prosecution has infringed upon the accused's rights," she wrote.
Van den Wyngaert, who is also a professor at the University of Antwerp, asked to be excused from trying the cases against Kenyatta and Ruto, saying her caseload at the court was already too great.
There was no suggestion that her resignation was linked to her criticism of the prosecution.