The trove was found hidden in plastic bags buried in woodland near Kazan
Colombian Edgar Alejandro Valero Valero allegedly confessed to stealing gems
They were reportedly taken from the suitcase of a jewellery store employee during transport to an expo in Kazan at the time of the 2018 football World Cup
After the heist, Valero fled Russia but was eventually tracked down in Argentina
Police said they had identified an unspecified number of Colombians and one Guatemalan as alleged suspects