A neighbour of the athlete Oscar Pistorius feared that the athlete might use the same gun he used to shoot his girlfriend to kill himself when he arrived to offer assistance.
Mr Pistorius covered his ears, looked down and again cried as Dr Johan Stipp, a radiologist who lives on the same Silver Woods Estate, described the scene on Mr Pistorius's driveway, shortly after Reeva Steenkamp's body had been carried outside.
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"The first thing he said was, 'I shot her, I thought she was a burglar and I shot her,'" Dr Stipp said.
Dr Stipp went on to describe in some detail the extent of Ms Steenkamp's injuries.
"She had no pulse in her neck. She had no peripheral pulse. There weren't any signs of life that I had seen. It was obvious to me that she was mortally wounded."
He said she had wounds on her right leg and arm, and that "blood, hair and brain tissue was intermingling".
"Oscar was extremely upset. He went back into the house, and I asked Mr Stander [the security guard] where the gun was. I was scared he was going to harm himself. Oscar was crying all the time. He said he will dedicate his life and her life to God if she would live," he added.
Earlier, Dr Stipp told the court how he and his wife were awoken by what "sounded like gunshots" and the sound of a woman screaming, becoming the fourth of Mr Pistorius's neighbours to claim to have heard a woman's voice, after the point at which his defence claims Ms Steenkamp had been killed.
Mr Pistorius is charged with premeditated murder after killing Ms Steenkamp through a locked toilet door on Valentine's Day last year.
He claims he shot her by mistake, thinking she was a burglar.
The trial continues.