Mystery surrounds Mexico's missing students, five years later

Relatives of some of the 43 missing students of Ayotzinapa, after meeting with Mexican President Andres Manuel Lopez Obrador.

Mexico City (CNN)Their faces have become emblematic in a country where violence seems to win over the rule of law. Mystery still shrouds their whereabouts and what happened on the day they vanished. But five years later, their families and Mexicans across the country remain determined to uncover the truth.

Forty-three students from a teachers' college in the town of Ayotzinapa, in Guerrero State suddenly disappeared on September 26, 2014. Surviving students and witnesses testified that they were attacked by local police, and according to Mexico's then-Attorney General, Jesús Murillo Karam, the Ayotzinapa students were kidnapped in a scheme that allegedly involved local officials, and then later handed over to the criminal group Guerreros Unidos, which operates throughout Mexico's southwestern region.
For the past five years, their parents have been demanding answers as to their whereabouts -- just a small part of the more than 40,000 people registered missing in Mexico, according to the Mexican government. No one has ever been convicted in connection to their disappearance.
The original investigation conducted by the administration of former President Enrique Peña Nieto has been widely criticized as ineffective and full of discrepancies, and now must be reviewed for failures of due process, according to Mexico's undersecretary of Human Rights Alejandro Encinas. Murillo Karam defended his handling of the case in an Aristegui Noticias interview this week with Carmen Aristegui, an anchor for CNN en Español. He maintained that the original investigation was carried out properly and offering to assist in any further investigation.
    Government prosecutors and investigators originally concluded that the group burned their bodies in a landfill and tossed their remains in a nearby river. But an examination by Argentine forensic experts contradicted the investigation by Mexican authorities. Information they gathered did not, "back up the hypothesis that there was a fire on the morning of September 27, 2014, of the required magnitude and duration that would've resulted in the massive incineration of the 43 missing students," the forensic team said. The Inter-American Commission on Human Rights also disagreed that that there was evidence to suggest their bodies had been burned.