The security guard, Pieter Baba, testified that Pistorius phoned him back moments after the initial brief conversation, but then started crying, didn't say anything and the line went dead. It was minutes after the double-amputee Olympian fatally shot Reeva Steenkamp, for which Pistorius is now on trial for murder.
"Not everything was in order as Mr. Pistorius was telling me," Baba recalled saying to a fellow guard as they were outside the runner's villa in the pre-dawn hours of Valentine's Day last year.
Baba's testimony followed a damaging description of Pistorius' character by a former girlfriend.
Samantha Taylor, who cried twice during her time on the stand in the Pretoria court, said that Pistorius always carried a firearm when they dated, sometimes shouted angrily at her and her friends, once shot his gun out the sunroof of a car, and that their relationship ended when he cheated on her with Steenkamp.
There were murmurs in court when Taylor revealed what she said was the reason for their relationship ending. Taylor said she started going out with Pistorius in 2011 when she was 17 and the relationship finally ended in November 2012.
Taylor described some of Pistorius' habits while they were dating, including what side of the bed he slept on at home and where he kept his gun during the night. Taylor's observations of what Pistorius did when they were together show different habits from what he says he did when he shot Steenkamp with his licensed 9 mm pistol.
Pistorius, 27, is charged with premeditated murder for killing Steenkamp, a 29-year-old model. Prosecutors charge he did it during an argument but he insists it was a mistake, and that he fired through the locked toilet door in his bathroom believing an intruder was behind it.
On the night Steenkamp died, security guard Baba had taken the short drive from the main gate of the enclosed estate to Pistorius' home with a colleague after neighbors called to report sounds like gunshots from that direction, the guard said.
He called Pistorius after seeing lights on in the house, and Pistorius told him everything was OK and the call ended. Soon after, Pistorius called back, said Baba.
"Maybe he wasn't sure about calling me back," Baba testified. "He just started crying over the phone. That's when the line went off."
A few minutes later, Johan Stander, a manager of the housing complex who Pistorius says he called to get an ambulance, arrived with his daughter and the group went to the front door of the house and someone pushed it open.
"I saw Mr. Pistorius coming down (the stairs) with Reeva," Baba said. "I was so shocked. I started regaining my senses when Mr. Stander said 'Oscar.'"
Stander then ordered Baba, who says he didn't enter the house, to go and call the police and an ambulance, the guard said.
Prosecutors are trying to build a case that Pistorius, one of South Africa's most celebrated sportsmen, intentionally killed Steenkamp after a fight and attempted to cover it up by saying he thought she was an intruder.
"Mr. Pistorius' exact words were, 'Security, everything is fine,'" Baba said when defense lawyer Barry Roux argued Pistorius actually said "I'm fine" on the call.
Earlier Friday, ex-girlfriend Taylor, wearing a white jacket, said Pistorius carried a gun with him "all the time" when they were together, and on one occasion he fired it out of a car's sunroof soon after a policeman stopped the car they were in for speeding. Taylor, who started dating Pistorius in 2011 after meeting him the previous year at a rugby match, described another incident in which she and Pistorius were followed by a car as he drove home.
"When we arrived at his estate, he jumped out of the car with his gun and held it to someone's window and then they drove away," Taylor said.
The court adjourned briefly after Taylor broke down in tears while describing how Pistorius also cheated on her with another woman, before he began his relationship with Steenkamp. It adjourned again when she wept while describing problems in her relationship with Pistorius, the first amputee to run in the Olympics.
Taylor said: "He cheated on me with Reeva Steenkamp."
Roux said he would produce emails between Taylor and Pistorius to show that was untrue, and he also sought to highlight apparent gaps in Taylor's memory of the sunroof shooting incident on a road in September 2012. Roux said Pistorius had denied the incident.
After prosecutor Gerrie Nel asked permission from the judge to uncover possible new evidence at the end of the former girlfriend's testimony, Taylor also described previous incidents when Pistorius thought there was an intruder trying to get into his home, and he reacted by waking her up, she said.
"There was one occasion when something hit the bathroom window and Oscar woke me up and asked me if I heard it," Taylor said. "He got up with his gun."
But he woke you up, Nel asked.
"Yes. There was probably one or two occasions when he woke me up to ask me if I heard something," Taylor replied.
Pistorius did not attempt to wake or locate Steenkamp before he shot her by mistake, according to his own version of events.