There is more than one artist using the name R.I.O.
1) R.I.O. is a german danceproject from the producers Manuel Reuter (Manian) and Yann Pfeiffer (Yanou). The vocals are from Neal Antone aka Tony T, who was in the nineties the rapper of Beat System. The project started in 2007. Read more about R.I.O. on Wikipedia.
2) R.I.O. is a british Grime artist. Born in Manchester, he spent some of his teenage years living on the Carribean island of St. Vincent, and even represented the Island in a World Cup qualifier against Cuba. Read more on Last.fm