Four suspected Russian mafia members, including reputed boss Andrei Petrov, have been arrested in the northeastern Spanish town of Lloret de Mar, sources involved in the investigation said Friday.

The detainees laundered some 50 million euros (roughly $67 million) in organized crime proceeds by investing for more than two years in all kinds of businesses in the Catalonia region, including restaurants, stores, gas stations and real estate, the sources said.

They said the businesses under investigation in the case had ties to Semion Mogilevich, one of the FBI's Ten Most Wanted, and were used to launder illicit funds from Russia.

The network, according to the same sources, was linked to the major Russian crime gangs Solntsevskaya and Solomonskaya and had companies and associates in the Seychelles, Cyprus, Andorra, Slovakia and the British Virgin Islands.

The defendants are scheduled to be arraigned on Monday before Spanish National Court Judge Eloy Velasco, who is in charge of the ongoing investigation.

Civil Guard officers confiscated a Kalashnikov rifle during a search of the home of the group's suspected leader. EFE