Transcript for Oscar Pistorius: Valentine's Day Murder?
The shock -- being sent the arrest of same -- Here's ABC's -- cunanan's. Oscar historian and -- Steen comp or one of the world's hot couples such -- -- David and Victoria or Brad and Angelina. But now the -- superstar runner is accused of murdering his bombshell cover girl on Valentine's Day Aaron -- Oscar the story. This has been arrested for allegedly killing his -- friends. Early Thursday morning neighbors in his exclusive gated community heard commotion and gunshots. -- -- -- -- confident that a young woman at the two year old woman that died on the scene and suddenly news. -- six year old man has been -- it and has -- charged with May Day. Police say -- accomplice shot four times with a nine millimeter pistol. The murders shocked to their fans around the world this is almost incomprehensible because Oscar mysteries wasn't just someone we celebrated free speech on the track. He is someone who celebrated. As a humanitarian. As a TrailBlazer. As a champion. -- From an -- to rivas career was just taking off the perfect combo of beauty and brains. The law graduate -- -- graced glossy magazine covers. And was about to star in -- reality TV show. She had been voted one of the world's 100 sexiest women by F HM magazine here she is on the cover shoot posted on YouTube. She was just -- really vibrant personality. And she had left really wicked. Since humans is really great -- fun to hang out with. Oscar it was an inspiration. -- to the blade runner this -- Olympic champion. He made history when he was the first to double amputee to compete in the Olympics. He was living the dream medals fame and lucrative endorsement deals like this one for Nike. Because -- addictions -- sufficient but kind of perceive -- smoking several team. You -- to grow yeah both teams committing other kids and be able Steve. The couple started dating just a few months ago man seemed happy earlier reports indicate -- -- may have sneaked into his home to surprise Oscar on Valentine's Day. And Oscar fired at mistaking her for burglar. -- had treated just the day before how much she was looking forward to the holiday. What do you have up your sleeve for Valentine's Day later adding it should be a day of love for every one may -- be blessed. But police were quick to make an arrest indicating that this wasn't the first time they dealt with Oscar. -- 10100 that there has previously been. Incidents at -- -- editorials and opinion. I'm not -- -- grateful that they had previously been incidents. That they're coming out charged him and they're talking -- previous domestic incidents. Makes it pretty clear that they think. That they know what happened there and they believe it was murder. His story is not only love steam and competition who had a passion for guns and was a regular at firing ranges each pleaded this picture of him taking a break from Olympic training. The world son Oscar is a charming soft hearted fighter. But those who knew him say he had a short temper and was often paranoid about his safety. South Africa has one of the highest crime rates in the world just a few months ago with the story is tweeted about possible break get news and how he would react. Nothing like getting home to hear the washing machine on church and thinking it's an intruder to go into full combat recon -- the into the pantry. The defense can't just -- I got it wrong. -- The defense would have to be I got it wrong. And here's why it was reasonable. For me to -- believed. That there was an intruder. But this isn't Oscar's first run in with the -- which is likely won't help his case. In 2009 -- an incident where she slammed a goal and a woman alleged. And he was arrested and charged with assault and spend the night in custody -- He was released the charges were dropped he was a hero to millions reaching Olympic glory in London competing alongside the world's fastest. A lot of people's time and distance -- in infants and and a lot of -- separate -- and and hardwood. Tonight Oscar historians is no longer living the dream and his spokesperson says he is cooperating with police. While the friends and family of his beautiful girlfriend are in morning. And the world is asking why. For Nightline -- -- on -- ABC news Pretoria South Africa.
This transcript has been automatically generated and may not be 100% accurate.