Tokyo Marathon winner Endeshaw Negesse has become the first Ethiopian named in connection with a failed drugs test following reports that as many as nine athletes from the distance running powerhouse are under investigation.
Negesse tested positive for meldonium, the same recently banned substance which it emerged that Sweden's Ethiopian-born former world 1500 metres champion Abeba Aregawi had failed for this week.
Official confirmation is expected today.
The identity of another Ethiopian marathon runner to have failed is also expected to be revealed.
Negesse beat reigning Olympic champion Stephen Kiprotich of Uganda en route to victory in Tokyo last year, crossing the line in a time of 2hours 06min 00sec.
This followed a personal best of 2:04:52 when finishing fourth at the Dubai Marathon in 2013.
The 28-year-old's other higher profile victory came at the 2012 Florence Marathon, where he won in 2:09:59.
This comes after Solomon Meaza, the general secretary of the Ethiopian Anti-Doping Agency, revealed how nine of the country’s runners were under investigation.
Five of them are “top athletes”, the official told Associated Press.
If Negesse's failure is confirmed, the case will mark yet another positive result for meldonium, a product which was only added to the World Anti-Doping Agency (WADA) banned list on January 1.
As well as Aregawi, Ukrainian biathletes Artem Tyshchenko and Olga Abramova have also failed for the substance, which can be used a metabolic enhancer to increase endurance.
The heart attack drug was moved from the monitored to the prohibited list by WADA due to “evidence of its use by athletes with the intention of enhancing performance”.
Russian cyclist Eduard Vorganov also failed for it last month.
There are suggestions that a Ukrainian doctor may have been involved in the transportation of the substance into Ethiopia.