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Pistorius On The Ropes: 'I Made A Mistake' In Trial Evidence

"You're trying to cover up for lies and I'm not convinced," prosecutor tells the double-amputee Olympian.

Prosecutors put Oscar Pistorius on the ropes again at his murder trial Friday, exposing “contradictions” in his version of events and forcing the athlete to admit making mistakes in his answers.

State lawyer Gerrie Nel challenged the Olympic athlete's statements that he was worried about crime before he fatally shot girlfriend Reeva Steenkamp through a closed toilet door in his home.

As Nel painted a picture of the accused as an unreliable witness, Pistorius said he was struggling to give consistent answers because he was tired.

Nel told him: "You're trying to cover up for lies and I'm not convinced."

The double-amputee sprinter claims he killed the model and law graduate after mistaking her for an intruder in the early hours of Feb. 14, 2013. He faces 25 years to life in prison if convicted of premeditated murder.

Olympic sprinter Oscar Pistorius poses next to his girlfriend Reeva Steenkamp. He is accused of premeditated murder.WALDO SWIEGERS / AFP - Getty Images file

Pistorius said he activated the sensors on the home alarm system before going to sleep on the night he killed Steenkamp, but feared that building contractors doing work on his house may have moved some of the security beacons.

Nel challenged why the so-called "Blade Runner" had not immediately raised concerns about the sensor, saying Pistorius was trying to build a story. "This is the biggest example of you tailoring your evidence," Nel said.

Nel said Pistorius had been unclear about the about whether he had turned the alarm on or off.

Pistorius said he "must have" turned off the alarm, which Nel described as a vague response.

The prosecutor then asked Pistorius, who acknowledged making a mistake in his testimony, if he needed time before continuing with his testimony.

"I don't need time," the Olympic athlete said, his voice quivering. "I am tired. It's not going to change. I’ve made a mistake. I said I must have switched it off. I can’t be sure that I said ‘I can’ or ‘I did’ switch it off because I don’t have an independent recollection of switching it off. So I must have switched it off or it would have gone off.”

Judge Thokozile Masipa interjected, asking Pistorius: “It is important that you should be ‘all here’ when you are in that witness box. If you are tired and the reason you are making all these mistakes is because you are tired you must say so. It doesn’t help to say it’s not going to change.”

“I understand, my lady,” Pistorius said. “I don’t have an independent recollection. Mr. Nel is right, my lady, I’m not arguing the point with him.”

“That’s not the question,” the judge replied. “The question is ‘are you too tired to proceed?’ because you can be at a disadvantage when you are in that box. It can’t be fair to you. It’s not fair to this court either. Are you making these mistakes because you are tired? Can we accept that … you haven’t made this mistake because you are tired?”

“Yes, my lady,” Pistorius said.

Nel asked why Pistorius had not reported previous crimes, including a burglary and an assault.

“There was a TV missing, I didn’t think anything could be done about it, I didn’t have insurance at the time,” Pistorius replied.

He also referred to comments made by Pistorius’ father, Henk, to a newspaper in which he said: “People must report crime to the police.” The athlete said he could not remember those comments.

He admitted that a downstairs window was broken and had yet to be fixed at the time of the fatal shooting, and felt safe enough to leave his cars outside the garage.

Pistorius said he had never been the victim of a crime on the upscale gated community where the he lived – but added pointedly that watches had been stolen by police officers who came to investigate the shooting.

Nel also asked Pistorius about a security scare more than five years ago in which the athlete says he was followed while driving and called a friend for assistance. After answering questions about the incident, Pistorius said he could not remember who he had called.

Nel said it was “improbable” that Pistorius could remember all the details of the incident except who he had called, and went on to suggest: “Because it never happened that you don’t want anybody to check up.”

“That’s not true,” Pistorius replied. “If I could remember who I phoned I would gladly give their name.”

Later, Nel once again challenged Pistorius’ claim that police must have moved items in the bedroom after the shooting, suggesting that the athlete – and not detectives - must have moved the duvet onto the floor. That would make it impossible for the athlete to claim he did not know Reeva had got up from the bed to go into the bathroom.

He also asked why the runner did not check if Reeva had also heard the sound the made him think there was an intruder. "Did you say, 'Did you hear that?'," Nel asked.

"I didn’t need confirmation," Pistorius replied.

Nel them reminded him that his previous girlfriend, Samantha Taylor, testified that in the past when he heard a noise, he discussed it with her.

"Are you getting emotional?"

Nel challenged Pistorius about why he approached the apparent source of the noise with his gun, asking why he would go towards danger.

As Pistorius grew frustrated with questions, Nel said: “Are you getting emotional?"

Pistorious cried as he retorted: “This is the night I lost the person I cared about. I don’t know how you don’t understand that.”

The trial continues.