Oscar Pistorius has maintained his story over the past year regarding what happened in the early morning hours of Valentine’s Day 2013, but now it appears that the stress of the trial may be getting to him.

The Olympic athlete said he heard sounds coming from his bathroom that morning and, because it was so dark in his bedroom, he didn’t realize his girlfriend, model Reeva Steenkamp, wasn’t in bed. What happened next has been the center of a year-long investigation that several witnesses can’t quite piece together.

Michelle Burger, who lives less than 600 feet from Pistorius, says she woke up that night to the sound of a woman’s screams and then heard a man’s voice calling for help. Following that, she says, there were four loud bangs and then the woman’s voice fading. According to Pistorius, he thought an intruder was in his home and fired four shots through the bathroom door. It was only then, he says, that he realized Steenkamp was in the room and not a stranger.

But according to Burger’s husband, Charl Johnson, the “intensity and fear in (the woman’s) voice escalated and it was clear that her life was in danger.” Another neighbor said the shouting went on for an hour and she had to put a pillow over her head to drown out the noise after being woken up.

“That’s when the first shots were fired. I remember hearing a succession of shots,” Johnson said. “I heard the lady scream again and the last scream faded moments after the last shot was fired.”

The confusion surrounding the chain of events that led to Steenkamp’s death have been a riveting point of the trial, but details of how Steenkamp was found and those surrounding her autopsy have had a visible effect on Pistorius, who broke down in tears with his head in his hands on Tuesday.

Pistorius claims he shot in self defense because he thought there was an intruder in his home, but has never denied killing Steenkamp.