Oscar Pistorius is back in court for the fifth day of his trial for the alleged murder of his girlfriend Reeva Steenkamp.
Neighbour Johan Stipp is continuing his testimony.
On Thursday, Dr Stipp told the court he found the South African athlete praying over the body of Ms Steenkamp as she lay dying.
The double amputee denies intentionally killing Ms Steenkamp, saying he mistook her for an intruder.
If found guilty, the 27-year-old, a national sporting hero dubbed the “blade runner”, could face life imprisonment.
‘Crying all the time’
In the trial’s first account of the moments after the shooting, Dr Stipp said he had tried to revive the 29-year-old model.
During his testimony, Mr Pistorius cried and seemed to retch.
Dr Stipp, who was testifying on the fourth day of the trial at the high court in the capital, Pretoria, said he could see Ms Steenkamp’s brain tissue in her hair.
It was at this point in the testimony that a police officer passed a plastic bag to Mr Pistorius.
Recalling the early hours of Valentine’s Day 2013, Dr Stipp said he had heard gunshots and after making sure it was safe, went to help.
When he got to Mr Pistorius’ house, he found the athlete kneeling by Ms Steenkamp, with “his left hand on her right groin, and his right hand – the second and third fingers – in her mouth”.
“I shot her,” the Paralympic star told him. “I thought she was a burglar.”
“Oscar was crying all the time,” Dr Stipp said. “He was praying to God [saying] `Please let her live.’”
Dr Stipp said Mr Pistorius had been in an emotional state, and fearing he might hurt himself, had asked where the gun was.
Before the trial was adjourned until Friday, Dr Stipp also testified that he saw a bathroom light on at Mr Pistorius’s house and a figure moving from right to left as a woman screamed.
The defence case is that all the screams came from Mr Pistorius.
Earlier, defence lawyer Barry Roux said that two neighbours, Michell Burger and Charl Johnson, had discussed their testimony with each other and amended the rough notes they had made a few days after the shooting.
“Your interpretation [of events] is designed to incriminate the accused and it’s unfortunate,” Mr Roux said.
Mr Johnson denied this. He insisted that he had heard a woman screaming “help”, followed by a man doing the same.
He rejected suggestions that the initial screams could have come from a man.
The state is seeking to convince the court that Mr Pistorius and Ms Steenkamp, a model, reality TV star and law graduate, had an argument before the athlete fired the shots that killed his girlfriend.
There are no juries at trials in South Africa, and his fate will ultimately be decided by Judge Thokozile Masipa.
Much of the case will depend on ballistic evidence from the scene of the shooting, correspondents say.