Bail decision looms for Oscar Pistorius NEW: "He must realize that long-term imprisonment is almost guaranteed," prosecutor says Prosecutors say they worry Pistorius will flee if freed on bail Pretoria, South Africa (CNN) -- South African prosecutors pushed Friday to keep Oscar Pistorius behind bars, painting the double-amputee track star as a killer offering an improbable defense in the shooting death of his model girlfriend. The picture offered by the prosecution came during the fourth day of a bail hearing that has been remarkable for not only its length but its allegations of miscues by a lead police investigator who himself faces attempted murder charges. Read more: What's life like in south African prison? Prosecutors are trying to keep Pistorius jailed pending his trial on a charge of premeditated murder in the February 14 shooting death of Reeva Steenkamp, 29. The judge, Chief Magistrate Desmond Nair, was scheduled to rule on the bail request at 2:30 p.m. (7:30 a.m. ET) on Friday. He must realize that long-term imprisonment is almost guaranteed. He might think he'll be acquitted," Prosecutor Gerrie Nel told the judge in a packed Pretoria courtroom. We all know that a lot of important people were granted bail and they stayed in the country. But lots of very important people have escaped. The prosecution has had several notable missteps during the bail hearing that began this week, including admissions by the lead investigator that police could have contaminated the crime scene and failed to properly catalog evidence. The South African Police Service pulled the investigator, Hilton Botha, from the case Thursday after prosecutors reinstated seven counts of attempted murder charges against him. Botha is accused of opening fire on a minibus full of people while allegedly drunk in 2011. Read more: Nike's bullet ad with Pistorius backfires Prosecutors allege that Pistorius, 26, killed his girlfriend after a heated argument in the early morning hours of Valentine's Day. Prosecutors say they are worried Pistorius will flee the country if he's released. But he has pledged to stay in South Africa and fight the charges, adding that he's unlikely to escape notice as a well-known athlete who walks on prosthetic legs. Prosecution plea The judge questioned the prosecution over its assertion Pistorius was a flight risk. What kind of life would he lead if he were to flee?, the judge asked. A life of freedom, the prosecutor said. Ducking and diving every day with those prosthesis?, the judge asked. A life not in prison, the prosecutor said. The prosecutor implored the judge to deny Pistorius' bail request , saying courts cannot favor the famous or the disabled. Nel pointed to the case of WikiLeaks founder Julian Assange, who fled to the Ecuadorian Embassy in London to avoid extradition to Sweden, where he is wanted for questioning over sex assault allegations. Assange's face was well-known, the prosecutor said, but "it didn't stop him fleeing arrest." Defense attorney, Barry Roux, disputed his client was a flight risk, saying the track star needs regular medical treatment for his stumps and his prostheses require routine maintenance. "Mr. Pistorius cannot go unnoticed through an airport due to his legs," he told the judge. Pistorius, eyes red, appeared emotional and drained. At one point, he sat with his eyes closed and shoulders shaking as tears rolled down his face. Other times, he seemed numb to his surroundings -- staring straight ahead. Court officials learned Thursday that prosecutors had restored the charges against Botha. The charges had previously been withdrawn for additional investigation, but prosecutors decided a day earlier to proceed, said Commissioner Riah Phiyega of the South African Police Service. Botha was replaced by the department's most senior detective, Vinesh Moonoo. The move, Phiyega said, positioned the department for a "long-haul" investigation of the killing. He argued police had missed a bullet where Steenkamp was shot and may have contaminated the crime scene by failing to wear protective foot covers. Botha said investigators didn't wear the booties because they'd run out. Accusations against the investigator will be little more than a "speed bump" in the Pistorius case, said Bulelwa Makeke, the spokeswoman for South Africa's National Prosecuting Authority. In arguments wrapping up during Thursday's session, the prosecutor said Pistorius' defense team has failed to explain why investigators found two cell phones and the gun believed to have been used in the shooting in front of the shower. CNN iReport: What my son taught me about Oscar Pistorius Pistorius made history last year as the first disabled athlete to compete in the able-bodied London Games. The case has roiled South Africa, where Pistorius is considered a national hero. Following his arrest on Valentine's Day, Pistorius put his career on hold and pulled out of future races. His sponsors, Nike and Oakley, suspended their contracts with the runner. If Pistorius is released on bail, he will resume training next week, said his coach, Ampie Louw. CNN's Michael Pearson, Ben Brumfield, Kim Norgaard and Diane McCarthy contributed to this report.