Protesters in Mexico City are marking four months since the disappearance of 43 rural teachers' college students in southern Mexico.

Demonstrators streamed through the streets from four starting points to converge at the capital's massive main square, the Zocalo. They brandished portraits of the missing, and signs demanding their return along with punishment for those responsible.

Prosecutors have said police kidnapped the students on Sept. 26 in the southern state of Guerrero and handed them over to drug gang members, who killed them and burned the bodies.

Protesters said Monday the government has failed to clear up doubts.

Student Omar Garcia says "there is no proof that convinces us that it happened like that."