Russia's former anti-doping chief Nikita Kamaev has died at the age of 52, reportedly of a heart attack.
His death comes just two months after he resigned from his post with RUSADA, the agency at the centre of Russia's biggest doping scandal.
Former RUSADA general director Ramil Khabriev said Kamaev is believed to have died at home after feeling pain in his chest while skiing.
Kamaev and Khabriev quit in December, a month after RUSADA was stopped from conducting drug tests by the World Anti-Doping Agency following accusations it had covered up cases of doping by leading Russian athletes.
"He complained of heart ache after a skiing session," said Khabriev.
"He has never complained about heart problems, at least to me. Maybe his wife knew about such problems."
Kamaev had initially responded defiantly to the WADA report released in November, branding the suspension of Moscow's anti-doping laboratory "utter nonsense" and ridiculing the allegations as reminiscent of "the epoch of James Bond."