Fresh questions have emerged over the "triangle" involving disgraced Tour de France winner Lance Armstrong, a payment by him to the International Cycling Union (UCI) and a drug-testing laboratory.
The UCI have admitted they accepted a donation of more than 100,000 US dollars from Armstrong in 2002, but have strongly denied it was connected to any cover-up of a positive test.
Armstrong's former US Postal team-mate Tyler Hamilton has testified that he [Armstrong] bragged he had managed to have a positive finding covered up. Around about the same time, the head of a drug-testing laboratory in Lausanne, Switzerland, admitted to meeting Armstrong and separately were also given free use of a blood analysing machine by the UCI.
A report by the USADA last week labelled Armstrong a "serial cheat" and a bully who enforced "the most sophisticated, professionalised and successful doping programme that sport has ever seen".
Dr Michael Ashenden, acknowledged as the foremost expert in blood doping and the man whose test caught Hamilton, said there were clear conflicts of interest. Ashenden told BBC Radio Five Live programme 'Peddlers - Cycling's Dirty Truth': "The UCI should never have accepted money from Armstrong under any circumstances.
"But if they took money after they were aware there were grounds to suspect Armstrong had used EPO, it takes on a really sinister complexion. We know Armstrong paid the UCI more than 100,000 US dollars and around that time the UCI gave the Lausanne laboratory free use of a blood analyser worth 60 to 70,000 US dollars.
"That's what I mean by a triangle: the laboratory meets with Armstrong, all of this takes place at about the time that Floyd Landis and Tyler Hamilton said under oath that Armstrong bragged he had managed to have a result covered up."
Dick Pound, the former president of the World Anti-Doping Association (WADA), said the UCI could have made greater efforts to have caught drug-taking cyclists.
He said: "They could certainly have done things to ensure they caught more people. It's generally acknowledged now that for a governing body to promote its sport and to police it puts them in an impossible conflict. The UCI have always been in a difficult position and their behaviour has not always been what you would hope it to be.
"There was certainly generalised knowledge that there had been some payments from Armstrong to the UCI. It's hard to think of the UCI as a charity and Lance somebody filled with [charitable] spirit."