South African paralympic star Oscar Pistorius has been arrested after reportedly shooting his girlfriend dead in the middle of the night after mistaking her for a burglar.
It happened at 4am this morning and the woman may have been killed after a Valentine's Day surprise went tragically wrong.
The dead woman is believed to be Reeva Steenkamp, 30, a former FHM model who has been dating Mr Pistorius since November.
She was shot in the head, the chest and the arm, police in the country have said, and Mr Pistorius will appear in court later this morning.
Just yesterday, Miss Steenkamp spoke excitedly on Twitter about her plans for Valentine's Day.
She said: 'What do you have up your sleeve for your love tomorrow??? #getexcited #ValentinesDay'
Replying to a follower, she later added: 'That sounds amazing! Wow that's what it's all about! It should be a day of love for everyone :) may it be blessed!'
Incident: Oscar Pistorius is believed to have shot dead his girlfriend Reeva Steenkamp, 30, a former FHM model, pictured together in November
Message: Reeva yesterday went on to Twitter to say how excited she was about Valentine's Day
The body of the woman has been removed from the house and the athlete is being questioned.
The track star lives on a large farm north-east of Johannesburg in the Pretoria region of South Africa, which is heavily guarded.
In an interview with the Mail before London 2012 it was revealed he slept with a pistol next to his bed and kept a machine gun by a window.
Miss Steenkamp, a law graduate from Port Elizabeth, gave an interview to the Sunday Times in South Africa last week where she described her boyfriend as 'an impeccable man who always her best interests at heart'.
Mr Pistorious, 26, is widely known as the Blade Runner, he is has also been dubbed 'the fastest man on no legs'.
He was the first double amputee to run in the Olympics and reached the 400 semi-finals in London 2012.
The Johannesburg-born athlete, who was born without fibulas in his legs and had the limbs amputated below the knee when he was 11 months old, had to win a legal battle over his blades with the International Association of Athletics Federations (IAAF) in 2008 for the right to compete in able-bodied competition.
Just three days ago, Pistorius tweeted about his excitement regarding his first race of 2013, accompanied by a photograph of him in action.
He said: '1 month till my first race of 2013.. Can't wait to burn it up!'
Star: Oscar Pistorius has reportedly been arrested this morning having shot his girlfriend in the head and arm, killing her
Scene: Police were called to Oscar's home, pictured, at 4am where a 30-year-old woman was treated by paramedics but died there
Death: Oscar Pistorius on his Pretoria at his house in Pretoria, where a woman believed to be his girlfriend was found shot dead today
Grand: Mr Pistorius lives in a large farm in Pretoria, which is surrounded by high walls and armed guards
South African journalist Kalay Maistry told Sky News: 'It is alleged that he thought his girlfriend, who’d come in to try to surprise him for Valentine's Day, was an intruder. It’s alleged that he shot her in the arm and head.
'I think what this actually highlights is the level of fear ordinary South Africans have.
'This is a man who has gone to bed, it’s an innocent surprise from a girlfriend … and the moment he thinks someone is trying to break in he grabs his gun.
'This has come as a complete surprise for a man who’s considered a national hero.'
Winner: Oscar Pistorius celebrates with his gold medal following the men's 400m win at London 2012
Star: The athlete is the most famous paralympian ever and the only disabled person to compete in the Olympics as well
South Africa has some of the world's highest rates of violent crime and some home-owners carry weapons to defend themselves against intruders.
Police spokesperson Katlego Mogale told the media that she could not confirm the man's identity until he appears in court.
She added that a 9mm pistol was recovered from the scene and a case of murder is being investigated. The woman was apparently shot four times.
Police are still busy with preliminary investigations on the scene, and statements are being taken from neighbours.
On Pistorius's website, a quote from Lord Coe from before London 2012 describes him as a 'real inspiration to people around the world', and a spokesman from sports giant Nike describes time with Pistorius as 'some of the most inspirational time we've ever spent around an athlete'.
Lord Coe said: 'Oscar is an extraordinary athlete who has made a significant impact in international sport.
'It will be fantastic to see him compete in London this summer - spectators can expect a real treat!
'He's been a real inspiration to people around the world so we were thrilled when he decided to join our International Inspiration programme as an ambassador, helping us to inspire young people worldwide.'
Arturo Nunez, Nike emerging markets marketing director, said: 'Nike routinely works with the best athletes in the world, and Oscar Pistorius stands out on that list.
'Many world-class athletes visit Nike and amaze our community, but the two weeks that Oscar spent on campus last summer went down as some of the most inspirational time we've ever spent around an athlete.'