The president of the Russian leading cosmetic retailer Vladimir Nekrasov, 47, and Semion Mogilevich, 61, were arrested on January 23 and charged with tax evasion.
Anna Usachyova said their custody had been extended from two to five months until June 23.
Mogilevich also known as Sergei Shnaider is a Ukrainian-born Russian passport-holder wanted by both Russian authorities and the FBI for involvement in organized crime and fraud.
Russian authorities allege that he was behind a tax evasion scheme said to have been used by Arbat Prestige.
Arbat Prestige was established in 1989 and opened its first retail outlet in 1998. It currently runs a network of 64 outlets across Russia. The company reported income of around $346 million in 2006.
