PRETORIA, South Africa -- Oscar Pistorius asked a friend to take the blame after a pistol was accidentally fired in a Johannesburg restaurant, weeks before the double-amputee runner fatally shot his girlfriend, a witness testified Wednesday at Pistorius' murder trial.

The testimony by boxer Kevin Lerena relates to firearms charges against Pistorius, and raises questions about the character of a man who insists he accidentally shot dead Reeva Steenkamp in his home in the early hours of Feb. 14 last year. Prosecutors allege he intentionally shoot Steenkamp, his 29-year-old girlfriend.

Lerena said the restaurant shooting happened when he and Pistorius and two other friends were in a restaurant in the swank Melrose Arch area of Johannesburg in January 2013. One friend, Darren Fresco, passed his gun to Pistorius under the table and told him that there was a bullet in the chamber, Lerena said. Then a shot went off, puncturing the floor near Lerena's foot had been, he said.

"There was just complete silence," said Lerena, who described being in shock and having blood where his toe was grazed in the incident. Then, he said, Pistorius apologized, saying: "Are you OK? Is everybody OK?"

Before the restaurant management approached the table, Lerena said, Pistorius asked Fresco to say he was responsible for the gunshot.

"'Just say it was you. I don't want any tension around me,"' Lerena remembered Pistorius saying. "'There's too much media hype around me."'

Lerena said they paid the bill and left the restaurant, and he never spoke about the incident. Two days after Pistorius shot Steenkamp, he said, he woke up to find over 100 missed calls on his telephone as media from around the world tried to contact him to ask about the restaurant shooting.

Earlier Wednesday, chief defence lawyer Barry Roux sought to undermine the prosecution testimony of a couple who say they heard a woman's screams and gunfire the night that Pistorius killed Steenkamp. Telephone records will show that the banging sounds the neighbours heard were not gunshots but a distressed Pistorius breaking down the toilet door with a cricket bat after realizing he had shot Steenkamp when she was in the toilet, thinking it was an intruder, Roux asserted.

Throwing doubt on the witnesses' recollection of the sequence is crucial for Pistorius' defence after the state maintained there was a loud argument on the night he shot Steenkamp through a door in his bathroom and screams and shouts before a gun was fired.

Pistorius' team wants to show the screams were Pistorius calling for help after the accidental killing.

Charl Johnson and his wife Michelle Burger have testified to hearing a woman screaming, a man shouting for help and then gunshots. During his cross-examination of Johnson, Roux said call records will show Pistorius called an estate manager at around 3:19 a.m. and soon after he bashed in the door with the bat.

In Johnson and Burger's testimony, they say they heard what they described as shots straight after making a call to security at 3:16 a.m. The similar times show the sounds were the bat on the door, Roux argued.

"There is only one thing you could have heard, because it coincides precisely," Roux said to Johnson. "That was the time that he (Pistorius) broke down the door (with the bat)."

Johnson replied, addressing the judge: "My lady, I am convinced the sound I heard was gunshots."

Pistorius, 27, was a globally admired athlete whose career peaked when he ran in the 2012 Olympics. He was born without fibula bones because of a congenital defect and his legs were amputated when he was 11 months old. He has run on carbon-fiber blades and is a multiple Paralympic medallist . He also competed at the London Olympics but didn't win a medal.