A blood doping expert says comments by a top cycling official that Lance Armstrong never took performance-enhancing drugs are "flabbergasting".
According to a US Anti-Doping Agency report, Hein Verbruggen, the honorary president of the International Cycling Union, claimed in 2011 that Armstrong had "never used doping".
But Dr Michael Ashenden told
BBC Radio 5 live
: "Any reasonable person would have at least said there was doubt."
Lance Armstrong: Usada reveals doping evidence
Verbruggen denies making the comments.
Ashenden, who has been an independent reviewer of blood profiles in cycling since 2008, continued: "For the honorary president of the UCI to say he [Armstrong] hadn't doped, in the face of everything, I really have to question what his motives were to say that. I find that absolutely flabbergasting."
Armstrong has been provisionally stripped of the seven Tour de France titles he won between 1999 and 2005 after
labelled him a "serial" cheat who led "the most sophisticated, professionalised and successful doping programme that sport has ever seen".
Usada's report quotes Verbruggen as saying in May 2011: "There is nothing. I repeat again: Lance Armstrong has never used doping. Never, never, never. I say this not because I am a friend of his, because that is not true. I say it because I'm sure."
Ashenden also raised questions about a "triangle" apparently involving Armstrong, the UCI and a drug-testing laboratory in Lausanne, Switzerland, formed as a result of a payment in excess of $100,000 (£62,200) the American cyclist made to the sport's governing body.
The UCI admitted it accepted a donation from Armstrong in 2002, but strongly denies it was connected to any cover-up of a positive test.
Ashenden added: "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 and around that time the UCI gave the Lausanne laboratory free use of a blood analyser worth $60,000 to $70,000.
"That's what I mean by a triangle. The laboratory meets with Armstrong. All of this takes place at about the time that [former Armstrong team-mates] Floyd Landis and Tyler Hamilton said under oath that Armstrong bragged he had managed to have a result covered up."
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