It has emerged that a former executive director of the Russian Anti-Doping Agency was planning to write a book about the doping culture in Russia before he died suddenly last week.

Writing in The Sunday Times, David Walsh published an email he received from Nikita Kamayev in which the former Rusada chief said he wanted to write a book about the truth about the anti-doping policies in Russia.

In the email, Kamayev writes:

''I want to write a book about the true story of sport pharmacology and doping in Russia since 1987 while being a young scientist working in secret lab in USSR Institute of Sports Medicine. Recent anti-doping controversies prompted me to write the memories associated with both my scientific studies and work in Rusada from 2010.'' 

Last Monday, Kamayev was found dead at 52, having been suspected to have suffered a ''massive heart attack.''

According to Walsh, Kamayev was a man who lead a healthy lifestyle and said that one of Kamayev's friends met him the day before his death and no issues of ill-health were mentioned by him.