PRETORIA, South Africa -- Oscar Pistorius argued with a police officer who handled his gun after a friend's car was stopped for speeding, the Olympic sprinter's murder trial heard on Tuesday.
"You can't just touch another man's gun," Pistorius' friend Darren Fresco recalled the athlete telling the traffic officer in late 2012. "Now your fingerprints are all over my gun. So if something happens, you're going to be liable for anything that happens."
Pistorius later fired a shot out of the car's sunroof without warning, Fresco said.
Fresco testified he "instinctively" moved over to the right side of the vehicle and away from where the gun was shot.
"He just laughed," Fresco recalled. "But it felt as if my ear was already bleeding."
In addition to the premeditated murder of his girlfriend Reeva Steenkamp, Pistorius is accused of three firearms violations. He has pleaded not guilty to all four charges.
Fresco also testified that at a busy Johannesburg restaurant he handed his gun, a Glock 27 .40 caliber pistol, under the table to Pistorius and the gun fired.
Fresco said Pistorius asked him to take the blame for the incident, which he did. The restaurant incident happened in early 2013, about a month before Pistorius killed the 29-year-old model and law graduate.
Pistorius opened fire through a toilet cubicle door at his home before dawn on Valentine's Day last year. The runner maintains he mistook his girlfriend for an intruder.
In earlier testimony, the chief lawyer for Pistorius questioned the methods of the pathologist who conducted an autopsy on Steenkamp.
Prof. Gert Saayman appeared at the High Court in Pretoria, South Africa, for a second day to give evidence on the gunshot wounds suffered by Steenkamp.
The pathologist said he had conducted between 10,000 and 15,000 autopsies over 30 years.
On Monday, the double-amputee vomited into a bucket in court while Saayman discussed Steenkamp's injuries.
However, NBC News correspondent Rohit Kachroo noted that Pistorius appeared "far more composed" on Tuesday.
The trial continues.
Jason Cumming of NBC News and The Associated Press contributed to this report.