Hundreds of people have marched through Mexico City to mark the first anniversary of the disappearance of 43 students in a murky case involving corrupt police that has haunted President Enrique Pena Nieto.
Parents and other relatives of the missing led the "March of National Indignation" from an area near the Los Pinos presidential residence, carrying large photos of their loved ones and shouting slogans decrying the official account of their fate.
"We came with a thirst for justice. There can be no impunity. Behind the 43 are thousands of disappeared," Sofia Rojas, a student at the National Autonomous University of Mexico, told AFP during Saturday's march.
Signs that read "Crime of the State" and "Out with Pena" peppered the crowd as they streamed down the Paseo de la Reforma, the grand boulevard that runs through the centre of the Mexican capital.
The parents of the missing students travelled from the violence-wracked southern state of Guerrero earlier this week and completed a 43-hour fast in honour of their sons on the eve of the protest.
Pena Nieto met with the frustrated parents on Thursday for only the second time, insisting that his government had not closed the investigation.
"We are on the same side," Pena Nieto told the parents. "We are searching for the truth together."
The president also ordered the creation of a special prosecutor's office to investigate the more than 20,000 disappearances in the country.
But the parents, who handed the president a list of demands, voiced disappointment and vowed to continue pressuring the government.
One of their demands was for a special unit within the attorney general's office to focus solely on the case, under international supervision.
The conclusions of the case have been disputed by the parents.
Scores of students from the Ayotzinapa rural teachers college in Guerrero travelled to the city of Iguala on September 26, 2014, to commandeer buses to join a commemoration in Mexico City.
Prosecutors say local police shot at their buses, killing three students and three bystanders.
The officers then delivered the young men to the Guerreros Unidos drug gang, which killed them and incinerated their bodies after confusing them with rivals, according to the prosecutors.
One student was positively identified among 17 charred remains sent to an Austrian lab while authorities said there was a possible DNA match for a second one.
Officials said on Friday that forensic investigators were sifting through some 60,000 more charred bone fragments to see if any can be tested.
The new forensic review came after independent experts from the Inter-American Commission on Human Rights questioned the official investigation, saying there was no evidence of a funeral pyre at the landfill.
The experts also urged authorities to investigate whether the students were attacked because one of the buses they seized may have contained drugs.