A South African court Wednesday ordered murder-accused paralympic athlete Oscar Pistorius to undergo psychiatric evaluation, media reported. Pistorius is on trial for fatally shooting his girlfriend Reeva Stenkamp through a locked toilet door February 14, 2013, at his house in Pretoria.

Pistorius has denied the murder charges and said that he shot Stenkamp, mistaking her for an intruder who had entered his house through the toilet window, but the state insisted that it was pre-meditated murder.

If found guilty of murder, Pistorius could face life imprisonment. If he is acquitted of that charge, the court will consider an alternative charge of culpable homicide, for which he could receive about 15 years in prison.

The state applied to have Pistorius referred for mental observation after a defence witness diagnosed the athlete with a general anxiety disorder (GAD). The prosecution argued Tuesday that psychiatric tests were essential and that he should be referred.

Judge Thokozile Masipa ruled that psychiatric evidence before the court could not replace “a proper inquiry” into his mental health.

Masipa said that according to South African Criminal Procedure Act, in case of an allegation of mental defect or illness, the accused must be sent for a referral, Independent Online reported.

Such an evaluation would ensure that Pistorius would get a fair trial, Masipa added.

Authorities say that the trial, which began in March, might get delayed further for months due to the psychiatric evaluation.