One of the top contenders for a gold medal at this year’s London Olympics–Alexander Dale Oen–has died at the age of 26. Officials say the cause of death was cardiac arrest.

Oen has been training with the Norwegian national team in Arizona and collapsed in the bathtub Monday night. His body was discovered after repeated attempts by his teammates to get him to answer the door. The death of such a young, immensely talented athlete has hit the team hard.

“We’re all in shock,” Norway coach Petter Loevberg said. “This is an out-of-the-body experience for the whole team over here. Our thoughts primarily go to his family who have lost Alexander way too early.”

Oen won the Olympic silver medal for the 100 breaststroke, the first swimming medal for his country, and just missed beating the world record for the best time in that category last year. Norway looked to him as a hero of sorts, someone who could stand for something good and powerful at a time when fear and chaos reigned after the deadly mass shooting last summer. A famous picture of Oen shows him pointing to the flag on his swim cap immediately after the race, showing support for his country at a time when they needed it most.

Oen’s last post on Twitter was made on Monday; he was anxious to get home after training.