Federal authorities sent badly burned remains to an Austrian medical university last month after finding them in a garbage dump and river in the southern state of Guerrero.
"One of the pieces (of bones) belongs to one of the students," a federal official told AFP on condition of anonymity.
Authorities say the aspiring teachers vanished after gang-linked police attacked their buses in the city of Iguala on September 26, allegedly under orders from the mayor and his wife in a night of terror that left six other people dead.
Parents of the students led a new protest in Mexico City on Saturday, the latest in a wave of demonstrations against President Enrique Pena Nieto's handling of the case.
