South African runner Oscar Pistorius is testifying again in his trial over the killing of his girlfriend, Reeva Steenkamp, at his Pretoria home last year.
Pistorius took the witness stand Monday as prosecutor Gerrie Nel cross-examined him for a fourth day.
The prosecution says Pistorius intentionally shot Steenkamp, and has questioned his reasoning for firing through a locked door into the bathroom where she was standing. Nel has used tough questioning to try to portray Pistorius as prone to anger and careless with guns, and pressed Pistorius to take responsibility for the killing.
The athlete insists he thought he was shooting at an intruder.
Pistorius is known as the "blade runner" for his carbon-fiber prosthetic legs. He has won many Paralympic Games medals, and was the first double amputee to compete in the Olympics.