Oscar Pistorius’s sister, Aimee, visited him Sunday. (Associated Press)

Oscar Pistorius, the Paralympian and Olympian charged with the murder of his girlfriend on Valentine’s Day, will return to a Pretoria, South Africa, court room Tuesday and Wednesday for a bail hearing.

Prosecutors will present their case that he should be held without bail until his trial, offering details about the shooting of Reeva Steenkamp in the early morning hours last Thursday and why they believe it was a premeditated murder. Pistorius is likely to enter a plea; his family members and representatives maintain that he is innocent. During a hearing Friday, Pistorius broke down and sobbed.

There were a number of developments in the case over the weekend, with South Africa’s City Press reporting that a bloodied cricket bat had been found at the home of Pistorius, where Steenkamp was killed. The newspaper reported that it is “the central piece of evidence in the unfolding murder investigation,” although investigators have not revealed just how it was used. City Press reported that Steenkamp’s skull was “crushed” before she was shot four times.

Police, according to the newspaper, are investigating possible scenarios involving the bat: that Pistorius, the 26-year-old double amputee known as “Blade Runner,” struck Steenkamp, a 29-year-old model and reality TV star, with it before shooting her; that she used the bat in self-defense; and that Pistorius used it to smash his way into the bathroom into which Steenkamp had run.

City Press constructed a timeline of events Thursday morning, put together from interviews with unnamed sources:

Pistorius’ father received a call from his son just after 3.20 a.m. on Thursday, asking him to come to his house. When his family arrived, Oscar was carrying Steenkamp’s body down the stairs from his bedroom to the entrance hall. Her head and arms were “dangling.”

He allegedly told his sister, Aimee, that something terrible had happened and that he had mistaken Steenkamp for a burglar. The police questioned Aimee and took a sworn statement from her.

Steenkamp was still breathing and Pistorius tried to resuscitate her in the foyer. Paramedics and police arrived on the scene and, minutes later, she was declared dead.

Steenkamp was wearing her nightie at the time. When the police inspected Oscar’s bedroom, they found her overnight bag and iPad on the floor. A holster for a 9mm pistol was found on Oscar’s side of the bed.

The bedclothes were crumpled. “It was clear that both of them had slept in the bed,” said a police source.

One cartridge was found in the bedroom and the police suspect Oscar may have “chased” her and fired the first shot before Steenkamp could lock herself inside the toilet.

“The suspicion is that the first shot, in the bedroom, hit her in the hip. She then ran and locked herself in the toilet. She was doubled over because of the pain. He fired three more shots. She probably covered her head, which is why the bullet also went through her hand,” said a source.

Steenkamp was shot in the head, hip, arm and hand.

Pistorius’s blood was tested for drugs and steroids and blood on the bat is being tested as well, City Press reported.

Assuming that Pistorius stands trial, the Associated Press reports that the South African court system is rooted in Roman-Dutch law, which means that there would be no jury trial. Instead, in the land in which Pistorius is a national hero, the trial would be conducted before a single judge, who can be assisted by two advisers, who usually are involved in assessing the technical aspects of evidence. The verdict is subject to appeal. There is no death penalty in South Africa.

Pistorius’s father, Henke, told the Sunday Telegraph that his son, who was a gun enthusiast, acted “on instinct” because he believed an intruder had entered the home.

“When you are a sportsman, you act even more on instinct,” he said. “It’s instinct — things happen and that’s what you do.”

Steenkamp is to be buried Tuesday.

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