Norwegian world champion swimmer Alexander Dale Oen has died of cardiac arrest while training in Arizona. The 26-year-old was in the city of Flagstaff preparing to compete in this summer's Olympics in London.

The Norwegian Swimming Federation said Dale Oen was found on a shower-room floor at the training facility late Monday.

Norway Swimming Coach Petter Loevberg told the Associated Press, “We are all in shock,” describing the immense grief as an “out-of-body experience.”

Dale Oen won the 100-meter breaststroke at the World Championships in Shanghai last July, just days after the killing of 77 people by confessed right-wing killer Anders Behring Breivik in Oslo and the island of Utoya. The swimmer dedicated his win to the victims of the massacre.

Dale Oen won a silver medal at the 2008 Beijing Olympics. He was considered one of Norway's top hopes for a medal at the London games.