Swiss skier Corinne Rey-Bellet, who won silver in the 2003 World Championships, has been shot dead at her parents' chalet along with her brother Alain.
Rey-Bellet was a star in Switzerland with a wide following
Their mother was seriously injured in Sunday's attack in the Swiss resort of Les Crosets but the skier's two-year-old son survived unhurt.
Police said a gunman had already fled by the time they arrived.
They have named Rey-Bellet's husband, Gerold Stadler, whose car was found nearby, as the main suspect.
Swiss police have issued an arrest warrant for Mr Stadler.
Magistrate Philippe Medico said Mr Stadler had been seen leaving the house carrying a gun.
The couple were reportedly having marital problems and recently separated.
Corinne Rey-Bellet shared a 2003 World Championship silver medal in the downhill event in St Moritz.
The speed specialist, who also won five World Cup races, retired shortly after her silver medal win because of a series of injuries to her right knee.
Swiss ski director Hansruedi Laich said he was shocked at the news: "To lose such a great skier in this way is tragic," he said.
Though injured, Rey-Bellet's mother managed to call the emergency services after the attack.
Corinne Rey-Bellet won several World Cup races
A police spokesman, Renato Kalbermatten, said they were trying to find the skier's husband, whose car was found in a nearby village.
"We'd really like to get in touch with him," he said, adding that the police had "no concrete indication" of the person responsible for the attack.
The skier's mother is being treated in hospital while her son has been placed in secure accommodation.
Her father has also reportedly been given protection.
Fans have left hundreds of messages of condolence on Rey-Bellet's website.
"We're shaken by the tragedy," the site's administrators said.
"We send our condolences to the family members and express our deep sorrow."