Source: Getty / Herman Verwey [1]

In early March, Olympic athlete Oscar Pistorius pleaded not guilty [2] to murdering his girlfriend Reeva Steenkamp a year ago, and the defense phase of the trial kicked off on Monday. Oscar took the opportunity to apologize to Steenkamp's family, and he also opened up about his childhood, the reason he fired the gun, and more. Meanwhile, testimonies from neighbors, one of Oscar's exes, a security guard, and a ballistics expert have also shed light on Oscar's case. Commonly referred to as the "blade runner" because of his prosthetic legs, the South African quickly became an Olympic idol thanks to six Paralympic gold medals and his ability to compete with able-bodied athletes.

Last year, though, that heroic image took a turn, because Oscar admitted to shooting and killing his girlfriend on Valentine's Day 2013. If he's convicted of premeditated murder, Oscar will face South Africa's mandatory life sentence with a minimum of 25 years. In the meantime, Oscar is selling the house [3] where the crime took place to raise money for his legal bills. Catch up on everything there is to know about the case.

Crime and Trial Details

• Now 27, Oscar admitted to shooting and killing Steenkamp on Feb. 14, 2013.
• The Olympian claimed that the murder was an accident, saying that his girlfriend was in the bathroom with the door closed, and he thought she was an intruder.
• Prosecutors charged Oscar with premeditated murder, and in the wake of the incident, sponsors like Nike and Oakley suspended their contracts with the athlete.
• Oscar pleaded not guilty to charges of murder plus three other counts related to the gun used in her killing and two separate gun indictments from earlier incidents.
• In Oscar's statement, the athlete said he'd been speaking to his girlfriend before he grabbed two fans from their balcony, and she must have gone into the bathroom while he was getting the fans.
• A few weeks into the trial, Oscar's lawyer said that Oscar is selling the house [4] where the crime took place, partly to raise money for his legal bills and partly because he "cannot contemplate ever returning to live there again."

Source: Getty / Alon Skuy [5]

The Defense Phase

• A key detail for the defense came when Oscar stated that he couldn't stand still without his prosthetics. "I don't have balance on my stumps," he said. "I can't stand still on my stumps." Previously, he said that he fired the gun because he knew he wouldn't be able to run away from an intruder or defend himself.
• Oscar opened up about his childhood, recalling that his father wasn't around very often and that his mother kept a firearm under her pillow, regularly waking up the kids if she heard something in the middle of the night.
• Oscar apologized to Steenkamp's family, saying, "I would like to take this opportunity to apologize — to Mr. and Mrs. Steenkamp, to Reeva's family, to those who are here today who knew her. I can't imagine the pain and the sorrow and the emptiness that I have caused you and your family. I can promise you that when she went to bed that night, she felt loved."

The Prosecution's Testimonies

• One of Oscar's neighbors, Michelle Burger, was the first witness to testify on March 2, and she recalled hearing "blood-curdling screams" from a woman followed by four gunshots. Her words contradict Oscar, who said he thought his girlfriend was in bed.
• The defense doubted whether Burger could hear a woman screaming inside a closed bathroom in a house 177 meters (about 581 feet) away.
• Another neighbor said she woke up to the noise of loud voices shouting for nearly an hour before she heard four distinct sounds, but she hadn't been sure they were gunshots.
• Burger's husband, Charl Johnson, echoed her testimony. Defense lawyer Barry Roux suggested that they purposely collaborated on their testimonies, saying, "You and your wife could just as well have stood together in the witness box. You failed, Mr. Johnson."
• Johan Stipp, a doctor who lived nearby, said he went to the house after hearing gunshots. There, he testified that he saw Steenkamp's body at the bottom of the stairs, where Oscar was bent over her with fingers in her mouth trying to clear her airway.
• Oscar broke down in the courtroom when Stipp said he believed that Oscar had wanted her to live. "He looked sincere to me," Stipp said. "He was crying. There were tears on his face."
• On March 7, Oscar's ex-girlfriend Samantha Taylor testified [6], getting emotional as she described a previous gun incident. She said that after a friend was pulled over for speeding, Oscar shot a gun through the car's open sunroof.
• Taylor also responded to a line of questioning about whether Oscar had ever woken her up because he thought he heard an intruder. She said yes, he'd done so several times.

Source: Getty / Leon Sadiki [7]

• A security guard who arrived at Oscar's house on the night of the murder, Pieter Baba, said that he called Oscar after neighbors reported the sound of gunshots. Oscar first told Baba that everything was "fine" but later called back and cried, not saying anything.
• When pathologist Gert Saayman testified about Steenkamp's injuries, Oscar reportedly covered his ears and started gagging, getting physically ill as the autopsy details were discussed.
• With multiple witnesses saying that they heard a series of screams, the prosecution said it was Steenkamp yelling in fear, while the defense claimed it was Oscar realizing that he'd shot her.
• On March 19, a police ballistics expert said he believed that Steenkamp was sitting [8] on a magazine rack in a defensive position, saying that her wounds signal that she was trying to cover herself.
• Based on the path of the bullets, the ballistics expert concluded that Oscar was likely not wearing his prosthetic legs. Last year, Oscar had claimed to have been wearing them, but in the first week of the trial, the prosecution agreed that he was not.
• A police officer downloaded Oscar and Steenkamp's WhatsApp messages and shared a text she sent Oscar weeks before she was killed: "I'm scared of you sometimes, of how you snap at me . . . You do everything to throw tantrums. I'm certainly very unhappy and sad."

Source: Getty / AFP / MARCO LONGARI [9]

Oscar's Olympic Background

• Oscar's first win came at age 17, when he took home the gold for the 200-meter T44 final at the 2004 Athens Paralympic Games.
• He quickly became known as an Olympic hero, competing as a double amputee in races for athletes with one leg.
• At the Paralympic Games in Beijing, he won three gold medals and was personally invited to meet Nelson Mandela.
• In 2012, Oscar became the first amputee runner to qualify for the Olympics, and although he didn't take home a medal in London, he's won six Paralympic gold medals in his career.

Source: Getty / Lefty Shivambu [10]

Reeva's Life Cut Short

• Steenkamp had the brains and the beauty: the law graduate also worked as a model.
• The TV personality had signed on to be part of the South African reality show Tropika Island of Treasure, and the program started filming two days after her death.
• The week before her death, celebrity gossip magazine Heat published what it claims to be Reeva Steenkamp's final interview [11]. She gushed about Oscar and said, "I don't want anything to come in the way of his career."