Oscar Pistorius Apologizes to Family for Killing Reeva Steenkamp; Tells Court 'I'm Scared to Sleep'

South African Paralympic athlete Oscar Pistorius, who is accused in the murder of his girlfriend Reeva Steenkamp, started his testimony at his murder trial Monday by apologizing to the family of Steenkamp, and said, "I'm scared to sleep. I have terrible nightmares ..."

"I was simply trying to protect Reeva," Pistorius told the court as he took the witness stand in his own defense at his murder trial in Pretoria on Monday, according to Reuters.

Prosecutors say Pistorius killed his girlfriend on Valentine's Day in 2013 after an argument. However, the Olympian claims it was an accident, that he fired four shots through a locked toilet door after he mistook her for an intruder.

"I'm scared to sleep. I have terrible nightmares about things that happened that night. I can smell blood. I wake up to being terrified," he was quoted as saying. "I wake up in a complete state of terror to the point that I would rather not sleep."

Pistorius told Steenkamp's relatives there "hasn't been a moment since this tragedy happened that I haven't thought about your family," according to BBC.

"I wake up every morning and you're the first people I think of, the first people I pray for. I can't imagine the pain and the sorrow and the emptiness that I've caused you and your family. I was simply trying to protect Reeva. I can promise that when she went to bed that night she felt loved. I've tried to put my words on paper many, many times to write to you. But no words will ever suffice," he said.

Defense lawyer Barry Roux said he has over a dozen witnesses to testify on "ballistics, urine emptying, damage to the toilet door, sound, and disability and vulnerability."

Pistorius said earlier that he has been reading the Bible and attending church and was being visited by a pastor.

"He's been going to church and people from the church are visiting him," Lois Pistorius, an aunt of the South African sprint runner, told The Guardian. "He attends the English service and I attend the Afrikaans service."

She added that the athlete is reading the Bible at home "a lot." "If you've got a purpose in life and you believe in God, it gives you a reason to understand things when they're not going smoothly because you rely on God who is everlasting and always there. Humans make mistakes. None of us is perfect."

Pistorius' uncle, Arnold, told M-Net channel in South Africa earlier that the athlete cries frequently. "He reads Scripture and he prays. He grieves all the time and, it's such a personal thing, it's difficult for me to talk about this but he's going through a very, very tough time."

The athlete's lower legs were amputated as a baby yet he achieved global fame as the "Blade Runner" due to his carbon-fibre prosthetic limbs.