Pistorius went with a cousin to a trendy Johannesburg nightclub on Saturday, where he was accosted by a man who aggressively questioned him about his murder trial, his family confirmed.
The man gave a different version, saying the double-amputee runner was drunk, insulted his friends and the family of President Jacob Zuma and poked him in the chest, according to Johannesburg's Star newspaper.
Regardless of who started the argument, the weekend episode focuses fresh attention on the disputed character of Pistorius, a globally recognized athlete who is on trial for murder after he fatally shot girlfriend Reeva Steenkamp through a closed toilet door on Feb. 14, 2013. Defense lawyers describe Pistorius, currently free on bail, as a vulnerable figure with a disability who pulled the trigger in a tragic case of mistaken identity, but prosecutors portray him as a gun-obsessed hothead who shot Steenkamp after the couple quarreled.
The trial is on a break ahead of closing arguments on Aug. 7-8, sparing Pistorius the near-daily trip to the Pretoria courthouse, where he has sometimes wept and wailed in apparent distress during testimony.
The nightclub argument has put him back on the front pages of South Africa's press, which has also highlighted a number of quotations about suffering and religious faith that appeared on his Twitter account in the hours that followed.
The altercation in the nightspot cannot be a factor in Pistorius' trial, said a legal analyst who has closely followed proceedings.
"It would not be appropriate to mention it in closing arguments as it would constitute hearsay as no previous witness has entered evidence of it on the trial record," Kelly Phelps, a senior lecturer in the public law department at the University of Cape Town, wrote in an email to The Associated Press.
"If it had occurred earlier in proceedings the gentleman concerned could have been called as a witness or Mr. Pistorius could have been questioned on the reports. Even then it would have very little value. The most important thing the court needs to determine is what Pistorius was thinking and how he was acting on the night in question," wrote Phelps, referring to the night on which Pistorius killed Steenkamp.
Pistorius had been barred from consuming alcohol under early bail conditions, but the ban was rescinded after the defense appealed.
He was seated in a quiet booth in the VIP section of the nightclub before he was approached, said Anneliese Burgess, a spokeswoman for the Pistorius family.
"The individual, according to my client, started to aggressively interrogate him on matters relating to the trial. An argument ensued during which my client asked to be left alone," she said in a statement. "Oscar soon thereafter left the club with his cousin. My client regrets the decision to go to a public space and thereby inviting unwelcome attention."
The man who argued with Pistorius is Jared Mortimer, according to Johannesburg's Star newspaper and The Juice, a South African celebrity news website, which quoted Mortimer as saying the Paralympic athlete started the confrontation.
Pistorius said Mortimer's friends had betrayed him in the murder trial, The Star quoted Mortimer as saying in an apparent reference to evidence presented in court. The athlete also said he had information that could get those friends into trouble, but he would not use it, according to Mortimer.
"He was drunk, but not bad. We were drinking tequila and I still remember putting down my drink and thinking I couldn't drink it while my friends were being spoken of like that," The Star quoted Mortimer as saying.
Pistorius also insulted the family of the South African president, Jacob Zuma, upsetting Mortimer, who is a friend of a member of Zuma's family, according to the newspaper.
"He was poking me and saying that I would never get the better of him," the newspaper quoted Mortimer as saying. "He was close to my face and at that point I pushed him to get him away from me. A chair was behind his legs and he fell to the ground."
The altercation happened Saturday night in Sandton, an upscale area in Johannesburg, according to South African media.
A woman who answered the telephone at The VIP Room, the club where the incident occurred, said club owner Chris Coutroulis was "overseas" and was awaiting reports from club staff who witnessed the altercation.
The club website says it caters to the "nouveau riche" and invites guests to "slip on your diamante dancing shoes or designer suit and dance the night away at the most ostentatious venue in Joburg."
On Monday, several quotations appeared on Pistorius' Twitter account. They included the biblical verse "The Lord is close to the brokenhearted," as well as a prayer, "Lord, today I ask that you bathe those who live in pain in the river of your healing. Amen."
Another tweet shows photos of Pistorius with disabled and other children and a caption about "the ability to make a difference in someone's life."
Burgess, the Pistorius family spokeswoman, said she was not immediately able to confirm the authenticity of the tweets. He last tweeted on Feb. 14, the first anniversary of Steenkamp's death.
Pistorius, who says he killed Steenkamp after thinking an intruder was about to attack him, faces 25 years to life in prison if found guilty of premeditated murder. He could also be sentenced to a shorter prison term if convicted of murder without premeditation or negligent killing. Additionally, he faces separate gun-related charges.