South African Paralympian Oscar Pistorius is seen in the dock on Thursday at the North Guteng High Court in Pretoria. The athlete's murder trial resumed today before a two-week postponement. Photo: AFP

The murder trial of Olympic and Paralympic sprinter Oscar Pistorius was adjourned Thursday until May 5 after the state wrapped up three days of punishing cross-examination of a forensic expert brought by the defense.

Judge Thokozile Masipa granted the state's request for a postponement to avoid conflicts with other cases. Prosecutor Gerrie Nel - nicknamed "The Pitbull" for his aggressive style - tore into defense witness Roger Dixon, questioning his credibility and expertise.

Pistorius, 27, is on trial for the murder of girlfriend Reeva Steenkamp, whom he shot dead with four rounds from a 9 millimeter pistol on Valentine's Day last year in his plush Pretoria house.

The track star insists he killed the 29-year-old law graduate and model after mistaking her for an intruder hiding in the toilet.

Dixon, a forensic geologist and former police officer, testified that Steenkamp was standing at an angle to the door with her arm out in front of her, suggesting she was reaching for the handle, when Pistorius shot her dead.

The testimony challenged the version of the state, which has sought to portray Pistorius as a gun-obsessed hot-head who murdered Steenkamp after an argument.

But Nel heaped scorn on Dixon's expertise, prompting Masipa to tell the advocate to restrain himself.

When the geologist said on Wednesday he tested the sound of a cricket bat hitting a wooden door to see if it could be confused with the sound of a gunshot, Nel asked: 

"Do you need to be an expert to do that? What expert skills did you use, wielding a bat? So your expertise was wielding a bat?"

Dixon confessed to being a "layman" with no professional experience in blood spatter analysis, forensic pathology or ballistics.

The trial, which has garnered massive domestic and international attention, is due to resume on May 5, two days before South Africa goes to the polls for a national election.

Reuters