Asbel Kiprop the Olympic and three times world champion over 1500m, has tested positive for a banned substance.
Kiprop was upgraded to the gold medal at the 2008 Beijing Olympics after Bahrain's Rashid Ramzi failed a drugs test. Kiwi Nick Willis was upgraded from bronze to silver.
Kiprop's agent, Federico Rosa, confirmed only that he had 'heard the same rumour' and was 'still trying to get confirmation'.
However senior athletics sources confirmed to the Daily Mail that the man widely regarded as the finest 1500m runner of the last decade has failed an out of competition test.
It represents a massive blow to athletics as well as Kenyan distance running when it was only last year that Jemima Sumgong, the Olympic women's marathon champion in Rio in 2016, tested positive for EPO and was banned for four years.
But it is a measure of the IAAF's willingness to catch even the biggest names since the formation of the Athletics Integrity Unit under the presidency of Lord Coe.
Kiprop has been on the start list of the opening Diamond League of the season in Doha since the event began in 2010 but he is not listed among the athletes to compete there this coming Friday.
The 28-year-old shot to prominence in 2008 when, aged just 19, he finished second in the Olympic 1500m final in Beijing. He was only narrowly beaten by Rashid Ramzi but his silver medal was upgraded to gold when the Bahraini runner tested positive for CERA, which is a modern form of EPO.
At the world championships Kiprop dominated his event, winning in 2011, 2013 and 2015, running the third fastest 1500m in history in 2015 too.
A report in Kenya on Tuesday said a 'high profile runner' who has 'dominated world championships over the years' was embroiled in a doping scandal.
And they claimed that, while there was no confirmation from the Anti-Doping Agency of Kenya (Adak) or Athletics Kenya (AK), their sources has said the substance was the same blood-boosting drug used by Sumgong.
Once considered the home of distance running, Kenya have had a rash of positive tests – in 2016 they reported 40 cases over the previous four years - with marathon star Rita Jeptoo also being caught using EPO. Like Kiprop she too was managed by Rosa, who was the subject of a doping investigation by the Kenyan authorities in 2016.
The case was, however, dropped before it went to court and Rosa said he was fearful that Kiprop had indeed tested positive. 'I recognise it's a big story but if it's true it will be very sad,' he said.
A spokesperson for the AIU said: 'For confidentiality reasons, the AIU cannot confirm or deny a query of this kind.'
In a tweet on April 29 Kiprop said: 'Jesus had to died for your conveniency. But rose for your dreams. He died for us. He is alive & so we shall.'