Lamine Diack was placed under formal investigation in France on Wednesday on suspicion of corruption and money laundering.
"The investigations will have to determine the origins of these sums," a spokesman for the prosecutor's office told Reuters on Thursday. "It's difficult to determine whether the entirety of it comes from the Russian athletics federation, but at least a part of it has gone through this federation."
Asked if he could confirm a media report saying that Diack was suspected of having received over a million euros in bribes in 2011 to cover up Russian athletes' positive doping tests, the spokesman said: "Yes."
The International Association of Athletics Federations (IAAF) that Diack, from Senegal and his early 80s, once headed said it was cooperating with the French investigation.
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Reuters has not been able to reach Diack's lawyer for comment. He has been released on bail of 500,000 euros ($543,000) and banned from leaving the country, the prosecutor's office said.
($1 = 0.9208 euros)
(Reporting by Chine Labbe; Writing by Michel Rose; Editing by Mark Heinrich)
