Uganda's Benjamin Kiplagat competes in the Men's 3000m Steeplechase Round 1 during the athletics event at the Rio 2016 Olympic Games. File / AFP
The Kenyan-born Kiplagat, 34, had represented Uganda internationally in the 3,000m steeplechase, including several Olympic Games and World Championships.
His body was found in a car on Saturday night on the outskirts of the Rift Valley town of Eldoret, home to many athletes.
"An investigation has been launched and officers are on the ground pursuing leads," local police commander Stephen Okal told reporters in Eldoret.
He said Kiplagat's body had a deep knife wound to his neck, suggesting he was stabbed.
Agence France-Presse