South African athlete Oscar Pistorius is due to reappear at Pretoria magistrates' court over the killing of his girlfriend Reeva Steenkamp.The prosecution is expected to serve the athlete with an indictment for the premeditated murder of his girlfriend. A trial date will also be set.Mr Pistorius, 26, denies murdering Reeva Steenkamp, saying he shot her after mistaking her for an intruder.He was granted bail in February and has since resumed some low-key training.The double amputee won gold at the London 2012 Paralympic Games and also competed at the Olympics.His arrest in February stunned many South Africans who saw him as a national sporting hero after his long legal battle to be able to take part in the Olympics.Ballistic evidenceState prosecutors are arguing that the killing was premeditated, a charge which carries a sentence of life imprisonment. They say he killed Ms Steenkamp intentionally after a fight.But Mr Pistorius denies committing murder, claiming he shot his girlfriend through the bathroom door of his upmarket house in Pretoria after mistaking her for a burglar.The prosecution is expected to hand over details of its case against Mr Pistorius at Monday's hearing, including a witness list and forensic reports.Much depends on ballistic evidence from the bathroom where Ms Steenkamp was shot, says the BBC's Africa Correspondent Andrew Harding.South African newspapers have reported that at least some of that forensic evidence appears to back up Mr Pistorius's version of events, he continues.However, the prosecution is expected to call witnesses who will say the Olympic runner was preoccupied with guns, and had been arguing with his girlfriend.Prosecutors told the Associated Press news agency that additional charges might be added to the indictment but did not offer any details.Last week, the police wrapped up their six-month investigation into Ms Steenkamp's killing."The South African Police Service is hopeful that justice will prevail," a statement from the office of South Africa's national police commissioner read.In June, Oscar Pistorius resumed "low-key" training as a way to help him "process the trauma", a statement on his website read.Mr Pistorius was freed on a bail of R1million (£74,000; $110,000). A court in March eased his travel restrictions, allowing him to leave South Africa to compete as long as he complied with certain conditions.