For hours Monday morning, as a prosecutor known as the “bull dog” hammered him on the minutiae of his story, Oscar Pistorius squirmed. He squirmed when discussing a LED light inside his room — why had it bothered him? He squirmed when describing how he allegedly spoke to his girlfriend the night of her killing — had it been a whisper, or a murmur? And he squirmed when Prosecutor Gerrie Nel called him a liar again and again.

“Your version is so improbable that it cannot be reasonably possible,” he told Pistorius. Then: “Because it’s not your version, it was never your version, it was a tailored version during cross examination.” Then: “Today I pick up you’re not sure about things. Is anything wrong? You’re fine?”

Pistorius, who said “he must have made a mistake,” had begun to touch at his eyes. He had said he “wasn’t sure” to question after question.

“My eyes are sore, my lady,” Pistorius ultimately said.

Monday’s inquisition marked the most pugnacious questioning Pistorius has received in a murder trial that’s reached its sixth week of testimony, and has captured international attention. The athlete known as the Blade Runner, the first double-amputee to ever compete in the Olympics, killed his model girlfriend, Reeva Steenkamp, last Valentine’s Day. That fact is not in dispute. What is at issue, however, was Pistorius’s intentions.

Did he, as he has claimed, think an intruder had entered his Pretoria mansion and, in a moment of fear, shoot his girlfriend four times with his 9mm by mistake? Or did the one-time national hero brutally murder her after they’d had yet another fight in a tumultuous relationship defined by them?

Throughout weeks of trial, Pistorius’s claims have repeatedly come into question. Several neighbors have testified they heard screaming that February night before gunshots, refuting Pistorius’s story that it had been a drama-free night. The athlete himself, who witnesses say is a gun aficionado with a bad temper, has emerged as a darker figure than his original media portrayal.

Pistorius’s fragile demeanor at trial, whether contrived or not, has contrasted with those assertions. Nearly every day of testimony, he has appeared weak and vulnerable, clad in dark suits and teary-eyed. Several times, he has vomited. And on Monday, the weeping continued.

“I then collected my firearm from under my bed,” Pistorius whimpered under examination. “…As I started walking, I told Reeva to get down on the floor and call police.”

“I wanted to chase the people out of my house,” he said, voice quivering.

Were you scared? Nel asked. “What did you achieve?”

His voice then turned to a bellow: “I screamed, I said, ‘Get the f— out of my house! Get the f— out of my house.” Then, face red and panting, Pistorius wept uncontrollably, the judge called a brief recess and Pistorius’s sister approached the witness stand to console him.

 (Interactive: Was the death a mistake or murder?)

Under questioning again, Pistorius said he inched into the bathroom, and ordered the perceived intruders to exit the bathroom. “I then moved forward, I had my pistol in front of me…,” he said. “I stayed as far away as I could from the wall to where the basins are around the corner.”

Pistorius was asked what he thought in those moments.

“Many many thoughts going through my mind. I was scared there might be someone that might come through the window… that there was someone in the toilet preparing to come out and attack me.”

But again, the prosecutor tripped the athlete up the details, and Pistorius stumbled over whether the bathroom door had been slammed or not.

“I’m not sure,” said Pistorius, shoulders hunched, face wan.

“I heard a noise and fired the firearm out of fear… I didn’t fire to kill anyone.”