Benjamin Kiplagat, who has represented Uganda at three Olympic Games, has been found dead in Kenya, with local reports saying he had been stabbed.
Kiplagat, 34, ran at the 2012 London Olympics in the 3,000m steeplechase.
He was reportedly found in a car with stab wounds to his chest and neck, near the Kenyan town of Eldoret, known as a top training centre for athletes.
World Athletics pocted on X: "World Athletics is shocked and saddened to hear of the passing of Benjamin Kiplagat. We send our deepest condolences to his friends, family, teammates and fellow athletes. Our thoughts are with them all at this difficult time."
Kenyan police say they have launched an investigation into his death.