In a sombre twist, the world-famous athlete will be served with the murder indictment on the day Steenkamp would have celebrated her 30th birthday.
Pistorius will be formally charged for the Valentine's Day slaying of the woman he says he loved dearly and killed by mistake, and will face a life sentence with a minimum of 25 years in prison if convicted of premeditated murder. Other charges could be added to the indictment. Prosecutors declined to comment on South African media reports on Friday that charges of recklessly discharging a firearm in public in two separate incidents would also be laid against the runner.
If the extra charges — reportedly relating to Pistorius shooting a gun out a moving car and firing one accidentally at a restaurant — are added, they may show the prosecution's aim to paint him as trigger-happy at his blockbuster trial next year.
The 26-year-old Pistorius denies he committed murder and says he shot Steenkamp through a locked toilet cubicle door in his bathroom in the early hours of Feb. 14 thinking she was a dangerous nighttime intruder. Prosecutors say he intended to kill her. A six-month police investigation ended this week, during which investigators reportedly focused on cellphones found at Pistorius' upscale home as well as the toilet door through which he shot.
The investigation team "is convinced that the accused has a charge to answer to," the national police commissioner's office said. Detectives, forensic experts, ballistics experts, forensic psychologists and technology experts had all worked the case, police said, gathering the evidence for trial and which could send Pistorius to prison until he is older than 50, at least.
National Prosecuting Authority spokesman Medupe Simasiku told The Associated Press that the exact date for the trial in early 2014 had not yet been set and would likely be decided on Monday, Pistorius' next scheduled appearance at Pretoria Magistrate's Court. The trial will be at the capital city's High Court and be before a judge. South Africa has no trial by jury.
The indictment papers will be served and the prosecution will retain a main charge of premeditated murder, Simasiku said, while only conceding that other charges are "possible."
In a statement, the National Prosecuting Authority said that it would be "inappropriate" to comment about "the charges" before they were presented in court. The language of the statement, using the plural charges, suggested that more could be added.
Pistorius' legal team also would not comment in detail on the charge or charges but a spokeswoman said his defence lawyers expect to see a copy of the indictment papers before Monday so they can prepare. The lawyers were locked in meetings on Friday, the spokeswoman, Anneliese Burgess, said.
Those indictment papers would also include additional information like a witness list and some details of the evidence police have gathered in the half a year since Pistorius fired four bullets from his licensed 9mm gun through the locked toilet door in the pre-dawn hours, hitting Steenkamp in the head, elbow and hip. One bullet missed her and was recovered from the toilet bowl.
Pistorius was initially charged with premeditated murder for bail purposes while police investigated the circumstances of the shooting, which has gripped millions and shone a spotlight on Pistorius' life.
The world's best-known disabled sportsman once inspired many by overcoming the adversity of losing his lower legs as a baby to win the right to compete against able-bodied athletes and qualifying to run at the biggest sports event of all, the Olympics.
Last Monday, photographs were published of Pistorius paddling in a kayak on a beach holiday with friends and standing on the sand, his pale prosthetic legs exposed in shorts in a rare public appearance.
This year's Paralympic and able-bodied world championships have flashed by without him, with Pistorius yet to run competitively anywhere since the killing and only using the sport that made him a huge star to help his mental state.
"Those close to him have encouraged him to spend a few hours a week on the track to assist him in finding the necessary mental and emotional equilibrium to process his trauma and prepare for the trial," Pistorius' family said in their last public statement.
Follow Gerald Imray at www.twitter.com/GeraldImrayAPSuggest a correction