Oscar Pistorius took the stand in his defense on Monday, saying he was trying to protect his girlfriend on the night she was shot to death in his home.

Pistorius, a double amputee who has competed in both the Paralympic Games and the Olympic Games, is on trial for the murder of Reeva Steenkamp on Valentine’s Day 2013. Early that morning, Pistorius says, he woke up to strange sounds coming from the bathroom adjacent to his bedroom. Fearing it might have been an intruder, he grabbed his gun and fired four shots through the bathroom door. The room was dark, he said, and he didn’t notice that Reeva wasn’t in bed. Neighbors say they heard screams coming from the home, but there have been conflicting stories as to whether there was an argument before the shots were heard. Prosecution claims that Pistorius, who has been in altercations involving firearms before, shot Reeva in cold blood after a fight, but the athlete says it was a tragic accident.

Pistorius says he has been in a “state of terror” since Steenkamp’s death and apologized to her family during his testimony.

“There hasn’t been a moment since this tragedy happened that I haven’t thought about your family,” he said. “I wake up every morning and you’re the first people I think of, the first people I pray for.”

Pistorius has been extremely emotional during the trial and has even gotten physically ill after being shown crime scene photos of his girlfriend. He now says he is on an anti-depressant and has trouble sleeping. At one point, he says, he crawled into a cupboard after waking up feeling panicked and had to call his sister to come be with him.

“I’m just in a complete state of terror,” he said. “I fall asleep and wake up like that.”

Pistorius faces 25 years to life in prison if convicted of first-degree murder.

Image via Wikimedia Commons