The double amputee could face a maximum term of 15 years in prison after he was found guilty of culpable homicide (manslaughter).
During today's lunch break, Schultz, who confessed to killing businessman Brett Kebble back in 2005, is believed to have mouthed "fuck you" to Aimee after seating himself in the court, according to The Telegraph.
Widespread reports have claimed that Aimee was left in tears following the alleged threat by Schultz, who escaped a previous murder conviction after he struck a deal with prosecutor Gerrie Nel.
Pistorius, who shot dead his girlfriend by firing four gunshots through a toilet door at his home in the early hours of Valentine's Day last year, is expected to be sentenced tomorrow.
The prosecution believes that the six-time Paralympic champion, who claims that he mistook Steenkamp for an intruder when he fired the gun, should be handed a prison term, while his defence argues that a three-year house arrest is an appropriate punishment.