Barry Steenkamp, father of Reeva Steenkamp, is embraced after her memorial service at the Victoria Park Crematorium in Port Elizabeth, South Africa on Feb. 19, 2013. South African paralympic and Olympic sprinter, Oscar Pistorius has been officially charged with premeditated murder for the alleged murder of his girlfriend and model Reeva Steenkamp. (MIKE SHEEHAN/EPA)

South African Olympian Oscar Pistorius on Tuesday denied that he murdered his girlfriend, instead claiming that he mistakenly shot her through a locked bathroom door at his home after believing there was an intruder in the house.

The 26-year-old double amputee, who became a global star at last year’s Olympics and Paralympics, made the statement in an affidavit read at a magistrate’s court after prosecutors accused him of the premeditated murder of Reeva Steenkamp, a South African model. “It [the belief] filled me with horror and fear of an intruder or intruders being inside the toilet,” the affidavit said, adding that Pistorius was “absolutely mortified by the events”.

“I had no intention to kill my girlfriend,” the affidavit said.

The arguments were part of a bail hearing at Pretoria magistrates’ court in a case that has stunned South Africa and the sporting world.

While the bail hearing took place, a funeral was held for Steenkamp in the coastal city of Port Elizabeth.

Pistorius was arrested last Thursday after police were called to his home in a gated complex in Pretoria in the early hours and discovered that Steenkamp had died from multiple gunshot wounds. Backing his argument that the killing was premeditated, Gerrie Nel, a prosecution lawyer, alleged that Pistorius had put on his prosthetic legs and walked seven meters to the bathroom.

“If I arm myself, walk a distance and murder a person, that is premeditated,” Nel said. “The motive is ‘I want to kill’ . . . this deceased was in a 1.4 by 1.14 meter little room. She could go nowhere. It must have been horrific.”

He said Pistorius – who in his affidavit admitted to keeping a 9mm pistol under his bed – fired four shots at Steenkamp, three of which hit her.

But in his affidavit, which was read by his defense lawyer, Barry Roux, Pistorius denied the allegations, saying: “I fail to understand how I could be charged with murder.” In the affidavit, he also said he had no intention of killing Steenkamp.

He said that after waking up in the early hours he heard noises in the bathroom, raising his suspicions of an intruder being in the house. It was “pitch dark”, he did not have his prosthetic legs on, “was vulnerable” and “felt a sense of terror rushing over me”, the affidavit said.

In the affidavit, Pistorius said he assumed Steenkamp was still in bed as he grabbed his pistol.

“I fired shots at the toilet door and shouted to Reeva to call the police,” his said in the document. “I felt extremely vulnerable as I didn’t have my prosthetic legs on and knew I had to protect myself and Reeva.”

It was only when he returned to the bedroom, that he realized Steenkamp was not in the bed. He then put on his prosthetic legs and smashed open the bathroom door with a cricket bat, the affidavit said.

He then carried Steenkamp down the stairs to take her to the hospital, but she died in his arms, the statement said. However, after hearing the prosecution’s arguments, magistrate Desmond Nair decided that Pistorius could face a charge of premeditated murder, meaning it will be harder for the sprinter to be granted bail.

The hearing was adjourned until Wednesday. Pistorius, who is nicknamed “Blade Runner” because of the carbon prosthetic legs he runs on, broke down several times during Tuesday’s proceedings as lawyers made their arguments and was taken back into custody.

Last year, he made history when he became the first double-amputee athlete to compete on the Olympic track, reaching the semifinals of the 400m after fighting for his right to compete against able-bodied athletes. In the affidavit, Pistorius said he earns approximately $630,000 a year.

Born without fibula bones in his legs, Pistorius has won numerous Paralympian medals and smashed a clutch of records during a career that has seen him take on the mantle of role model and inspiration for his determination to overcome adversity and compete at the pinnacle of athletics.