On the first day of Oscar Pistorius' cross-examination by the prosecution on Wednesday, lead prosecutor Gerrie Nel confronted Pistorius with a forensic photograph of his girlfriend, Reeva Steenkamp, after he had shot and killed her. One of the four shots fired by Pistorius struck Steenkemp in the head, and the picture showed the graphic wounds.

Nel told the Olympic and Paralympic runner he should "take responsibility" for killing Steenkamp and said "it's time that you look at it," referring to the photo.

Pistorius turned away from a TV monitor that was showing the photo and said while sobbing, "I don't have to look at a picture, I was there."

Pistorius claims he mistook Steenkamp for an intruder when he fired through a closed bathroom door on Valentine's Day 2013. The prosecution alleges Pistorius murdered Steenkamp.

The cross-examination began with Pistorius saying he had "made a mistake" when he fired the shots that killed Steenkamp.

"You killed a person, that's what you did," Nel said in response.

Target practice video

A video of Pistorius was shown to the court as well. It was broadcast before the start of the trial by Sky News and showed him, prior to Steenkamp's death, firing a handgun at a watermelon before quipping, "It's a lot softer than brains, but it's like a zombie stopper."

Nel said Pistorius had shot the watermelon to see what a bullet hitting a person in the head might look like. He added that "the same thing happened to Reeva's head: it exploded," before displaying the picture of Steenkamp to the court.

Earlier in the defense's questioning of Pistorius, the man known as the Blade Runner for his prosthetic lower legs that he wore to compete in track competitions described what happened after he fired through the door and hit Steenkamp.

He said he used a bat to break down the door where he found Steenkamp "struggling to breathe." Pistorius then said he carried her downstairs near the front door to wait for help to arrive. She was bleeding heavily and "had died while I was holding her," he said.

Pistorius faces 25 years to life in prison if he is convicted of premeditated murder.

mz/dr (AP, Reuters, dpa)