Kenyan former world 800-meter bronze medallist Kipyegon Bett died on Sunday from kidney and liver failure at the age of 26.
Bett was banned by the World Athletics Integrity Unit (AIU) in August 2018 for four years after he tested positive for the performance-enhancing substance erythropoietin (EPO).
He denied ever using the blood-boosting drug.
His ban prevented him from participating in the 2020 Tokyo Olympics and the 2022 World Championships in Eugene, Oregon.
"He went into a depression and started drinking heavily. We tried to encourage him to go back to the track after his suspension ended in August 2022 but he didn't put in much effort," Bett's sister Purity Kirui told AFP on Monday.
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Kirui said Bett had been taken into hospital in his hometown of Kericho in western Kenya a week before his death.
He was later discharged but then readmitted on Friday after his condition worsened.
"He had been having problems with his kidneys. But later the doctors realised that his liver was failing as well and they prescribed some drugs for him on the first visit to the hospital, only for the doctors to discover that both of his organs had failed before he passed on Sunday at 11 am."
Bett won the world Under-20 800m title in Bydgoszcz, Poland 2016, and took the bronze medal at the 2017 World Championships in London.
He had also demonstrated his prowess earlier in 2017 when he powered to victory in the Shanghai Diamond League meet, eclipsing a strong field that included compatriot David Rudisha, the 2012 Olympic gold medallist and world record holder, who finished fourth.
