"Four young people were arrested. All of them are Russians. Now they are being interrogated at the Voronezh central prosecutor's office," said Pavel Bolshunov, the head of the public relations department of the FSB.
Amaro Antonio Lima, a 24 year-old Guinean student at the Voronezh Medical Academy, was stabbed to death on February 21.
The Voronezh central prosecutor's office initiated criminal investigation of the murder.