The double-amputee, known as "Blade Runner" for the prostheses he wears in competition, is due in court on August 19 for a hearing that will likely be brief and procedural. He was released on bail in February after being charged with murder.
Police said on Tuesday they had used forensic experts, ballistics experts, psychologists and technology experts to investigate the February 14 death of Reeva Steenkamp, who was shot by Pistorius through a closed bathroom door at his upmarket Pretoria home.
"It is expected that he will be served with an indictment and that the matter will be postponed. The prosecution, in collaboration with the defence team, will agree on a trial date," police said in a statement.
In the South African legal system, an indictment is a more detailed charge sheet that is used to move a case from a lower court to a high court.
Pistorius, 26, has admitted to firing four shots at Steenkamp, 29, hitting her in the head, arm and hip.
South African police stumbled in their initial investigation and were forced to replace their lead detective when it emerged he was facing attempted murder charges for shooting at a minibus.
The new investigator, appointed in late February, has handled some of the country's highest-profile cases.
In pre-trial testimony, Pistorius's lawyers told a magistrates' court the shooting had been a tragic mistake and the athlete was acting in self-defence against what he thought was an intruder.
Prosecutors accused him of premeditated murder for killing Steenkamp, a noted model and budding reality TV star.
Pistorius was one of the most celebrated athletes of the 2012 Olympics and Paralympics in London, making the Olympic 400m semifinal and winning Paralympic gold over the same distance.
His arrest and subsequent murder charge a few months later shocked millions around the world.
In South Africa, his triumph over adversity made him a hero for both blacks and whites, transcending the racial divides that persist 19 years after the end of apartheid.
Pistorius has mostly kept out of the public eye since he secured bail. He has had one court appearance, in June, which lasted about 10 minutes.
(Reporting by Jon Herskovitz)
