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, reached the semi-finals of 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.
Kenyan police say they have launched an investigation into his death.
World Athletics said it was “shocked and saddened” by news of Kiplagat’s death.