"All three detainees have given evidence, confessing [to the attack]. Their apartments have been searched and components of explosive devices found," he said.
He said earlier that Ilya Tikhomirov and Oleg Kostyrev, who had planted the bomb, had been charged with the premeditated murder of two or more people on grounds of ethnic and racial hatred, while the third suspect, Valery Zhukovtsov, was supposed to cover their escape.
Syomin said Tikhomirov and Kostyrev had agreed to carry out a bomb attack at the market "because there [were] too many people of Asian backgrounds, whom they intensely disliked."
But the prosecutor said that the suspects did not belong to any extremist groups.
The prosecutor also said seven of those killed in the bombing attack had been identified. "Two of them are Russians; three are Tajik citizens, and two are Uzbek nationals," he said.