The former head of Russia’s federal anti-doping agency, Rusada, has died unexpectedly, two months after resigning from his post following a doping scandal involving Russian athletes. He was the second senior Rusada official to die this month.

Nikita Kamayev, 52, suffered a “massive heart attack” at his home on Sunday after cross-country skiing, Rusada has confirmed.

“It’s a very unexpected death,” the Russian Sport Minister, Vitaly Mutko, told Russia’s R-Sport agency. “The man seemed healthy and everything was fine.”

Vyacheslav Sinev, the agency’s general director until 2010, died on 3 February. The cause of his death is unknown.

Anna Antseliovich, the acting head of Rusada, told R-Sport that during the five years Mr Kamayev had spent working at the agency, “he had never complained of heart problems and wasn’t sick”.

The former general director of Rusada, Ramil Khabriyev, told Russian news agency Tass that Kamayev had complained of heartache after a skiing session. “He had never complained of heart problems, at least not to me. Maybe his wife knew about such problems,” Mr Khabriyev said,

Mr Khabriyev resigned at the same time as Kamayev and a number of other senior executives in December last year, four weeks after the World Anti-Doping Agency (Wada) released a damning 323-page report that accused Russia of widespread corruption and state-backed cheating system in international sporting events.

The report alleged that Russian trainers, coaches, doctors and even Russian anti-doping officials were complicit in warning athletes ahead of surprise tests, covering up failed test results and helping athletes acquire illicit performance-enhancing drugs.