Pretoria: Oscar Pistorius was in the process of buying six guns at the time he shot dead his girlfriend Reeva Steenkamp, with a revolver marketed as “the world’s most powerful handgun” on top of his list, his murder trial heard on Monday.

The Olympian had been invoiced for the Smith & Wesson 500, as well as three shotguns, a rifle and a 38-calibre revolver just prior to the fatal shooting.

But the court also heard evidence Pistorius had a sound knowledge of South African gun laws, answers to a licensing revealing he knew exactly when lethal force could be used against intruders.

Pistorius claims he mistook Ms Steenkamp, who was behind a closed toilet cubicle door in his Pretoria home, for a burglar.

Gun licenser Sean Rens told the Pretoria High Court on Monday that he had spoken to Pistorius about his “great love and enthusiasm” for firearms when the pair met at his firearms training academy south of Johannesburg,

Mr Rens said Pistorius had scored highly on his licensing requirements, answering correctly that a person could only shoot at a person if his life was directly threatened.

The test posed a series of situation-based questions, including whether he could open fire on thieves stealing a television from his home.

Pistorius answered in the written exam: “No. Life is not in danger.”

A follow-up question asked if he could shoot at an intruder advancing toward him brandishing a firearm, when there was nothing between them.

The 27-year-old disabled athlete correctly answered “yes”.

The questionnaire also asked about the importance of “target identification”, to which Pistorius answered: “Know your target and what lies beyond.”

The evidence may prove important to the state’s case for premeditated murder, with the athlete’s answers revealing he well knows that deadly force cannot be used against a non-hostile intruder. He has admitted firing blindly into the toilet cubicle, believing there to be an intruder there.

But the state argues the pair had been arguing, and Pistorius murdered his law-graduate and model girlfriend in cold blood.

The double-amputee’s order for the six weapons – more than allowed under South African law – was cancelled a month after Ms Steenkamp’s death, Mr Rens said.

Unless formally registered as a firearm collector, South Africans cannot own more than four weapons.

At the time of the shooting, Pistorius only owned the 9mm pistol which killed Steenkamp.

Evidence given in the first two weeks of the trial has suggested he took the gun everywhere, even leaving it within reach while in bed at night.

Mr Rens told the court Pistorius had admitted once entering “full combat mode” after mistaking a washing machine for an intruder.

In November 2012, Pistorius had tweeted jokingly about the incident: “Nothing like getting home to hear the washing machine on and thinking its an intruder to go into full combat recon mode into the pantry!” The post has since been deleted.

Under cross-examination, Mr Rens told the court Pistorius’ actions in going into “code red” mode in response to a sound in his house was in line with the training he would have received.

The 11^th day of the murder trial was also the day Ms Steenkamp’s mother June returned to the court for the first time since its opening day a fortnight ago.

In what may have been the pair’s first interaction since the Valentine’s Day shooting, Pistorius appeared to greet Mrs Steenkamp formally as he passed her in the court room and she seemed to acknowledge him in return.

Pistorius’ sister Aimee also approached Mrs Steenkamp, kneeling beside her and speaking to her for several minutes.

However, the grieving mother quietly left the court room mid-morning as image of Pistorius covered in her daughter’s blood were shown during evidence from a crime scene photographer.

Other photos shown during the evidence of Bennie van Standen on Monday revealed blood splatter on bedsheets and a bedroom wall, suggesting a possible tussle the night Ms Steenkamp died.

The trial continues on Tuesday.