The judge in the trial of South African athlete Oscar Pistorius has ordered that he should undergo a mental evaluation.
She ruled psychiatric evidence before the court could not replace "a proper inquiry" into his mental health, the BBC reported.
Correspondents say the trial, which began in March, will almost certainly face a lengthy delay.
The prosecution argued on Tuesday that psychiatric tests were essential and that he should be referred. The defence vigorously opposed the move.
Mr Pistorius denies intentionally killing girlfriend Reeva Steenkamp on Valentine's Day last year.
He says he accidentally shot her through the toilet door in a state of panic, mistaking the 29-year-old model and law graduate for an intruder.
