The 28-year-old Bett, the father of two-year-old twins, made his name at the World Athletics Championships in Beijing where he surprised the field by taking gold. He has since struggled to replicate that form.
Bett, whose twin brother Aron Koech is also an international 400m hurdler, was disqualified in his heat at the 2016 Rio Olympics after hitting a hurdle and was unable to defend his world title in London in 2017 due to injury.
"It is very sad because I talked to him yesterday. He had gone to Nairobi Hospital to see a doctor because of the injury he picked up in Asaba," said Barnaba Korir, an official with Athletics Kenya (AK).
"This morning we got the reports (of his death) and, as AK, we are saddened beyond words."
Track and field's governing body, the IAAF, said it was "deeply saddened and shocked" by the news.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)