Russian federal investigators said Friday they had sent the World Anti-Doping Agency "proof" refuting claims by whistleblower Grigory Rodchenkov of a state-sponsored doping programme at the Sochi Olympics in 2014.
"The investigators have collected objective proof refuting Rodchenkov's deceitful evidence concerning the delivery of athletes' doping samples to the Sochi anti-doping laboratory," the Russian Investigations Committee said in a statement.
The committee said it had sent WADA documents relating to the registration of doping samples that contradicted the whistleblower's allegations, according to the statement on its website.
The body, which reports directly to the Kremlin, opened an investigation into the scandal in 2016.
Former Russian Anti-Doping Agency chief Rodchenkov provided key evidence leading to suspensions of Russian athletes from global sport, including a ban from competing under the Russian flag at February's Pyeongchang Winter Olympics.
The suspensions followed revelations based on Rodchenko's evidence concerning a vast state-sponsored doping scheme that included charges that tainted urine samples were switched with clean ones at the Sochi Games.
Rodchenkov fled to the United States in late 2015 and went into hiding, saying that Russian President Vladimir Putin wanted him dead for his role in exposing the doping conspiracy.