Prosecutor: Pistorius should get mental evaluation

May. 13, 2014 6:25 AM EDT

PRETORIA, South Africa (AP) - The chief prosecutor in the murder trial of Oscar Pistorius has asked that the double-amputee runner be placed under psychiatric evaluation after an expert witness testified that he had an anxiety disorder.

Prosecutor Gerrie Nel on Tuesday noted that a psychiatrist for the defense had testified that the disorder that she diagnosed in Pistorius may have played a role in his fatal shooting of girlfriend Reeva Steenkamp in his home on Feb. 14, 2013.

Nel has acknowledged that an evaluation of Pistorius' state of mind at a government facility could mean the trial will be delayed. On Monday, he referred to a 30-day evaluation period.

Pistorius says he mistook Steenkamp for an intruder when he shot her. Prosecutors say he killed her in anger after an argument.