Regional chief prosecutor Aleksandr Ponomaryov said today that 12 of the 13 were in custody. He said one of them, who was accused of knifing the student, faces murder charges.
According to RIA Novosti news agency, three others face robbery charges and the remainder are charged with hooliganism.
Ponomaryov said all the defendants are facing an additional charge of carrying out a crime for racial reasons.
Enrique Arturo Angeles Hurtado -- who was attending Voronezh State University -- was attacked by about 15 local youths at a sports complex in the center of Voronezh, some 475 kilometers south of the Russian capital Moscow.
The killing prompted a formal protest from Peru.