Mexican forensic experts have identified from charred remains at least one of 43 students who went missing in Guerrero state.
A family member of one of the students, Alexander Mora, confirmed that the remains identified were his.
The students were allegedly seized by local police in the town of Iguala in September and given to a criminal gang.
Prosecutors say the gang killed them and burned their bodies at a rubbish dump near the town of Cocula before scattered their ashes in a river.
The students’ disappearance has triggered widespread protests across Mexico against corruption and violence.
Another demonstration was held on December 6 in Mexico City at which parents of students spoke about the identification.
“If [the government] thinks that, because one of our boys’ DNA was identified, we will sit and cry, we want to tell them that they’re wrong,” Felipe de la Cruz, father of a missing student, told the crowd.
“We will keep fighting until we find the other 42.”
The unrest has seen President Enrique Pena Nieto’s popularity rating drop to its lowest point since he took office two years ago.
In response, Enrique Pena Nieto has submitted a package of reforms to Congress that include replacing all 1,800 municipal police forces with state-level units.
The students had travelled from a teacher training college in Ayotzinapa to Iguala to protest against what they said were discriminatory employment practices for teachers which favor urban students over rural ones.
Police opened fire on the students, who were in buses travelling back from Iguala to their college. Three of them were killed and three more people in nearby vehicles also died.
A busload of the students tried to flee but was chased by municipal officers who then took them to the local police station.
Some of the officers, who have since been arrested, told investigators they then handed the students over to a drug gang called Guerreros Unidos (United Warriors).
Iguala Mayor Jose Luis Abarca and his wife, Maria de los Angeles Pineda were arrested in the beginning of November in Mexico City.
Mexican officials accused Jose Luis Abarca of ordering police to confront the students to prevent them from disrupting a public speech given by his wife.
More than 70 other people have been arrested in connection with the disappearances.
Mexico’s Attorney General Jesus Murillo has said that suspected gang members have confessed to killing 43 students missing for six weeks.
Jesus Murillo said three alleged gang members claimed the students were handed over to them by police.
They said some were already asphyxiated and they shot the others dead, before setting fire to all the bodies.
A total of 43 students went missing after clashing with police on September 26 in the town of Iguala.
The suspects from the Guerreros Unidos drug gang were recently arrested in connection with the disappearances.
Relatives of the missing said they had been told that six bags of unidentified human remains had been found along a river near where the students vanished.
Jesus Murillo warned that it would be difficult to identify the charred remains and that authorities would continue to consider the students as missing until DNA tests confirmed the identities.
Previous searches have uncovered mass graves in the area, but initial tests suggested they did not contain the remains of the students.
Jesus Murillo showed videotaped confessions by the suspects who said they had loaded the students into dumper trucks and taken them to a landfill site in Cocula, a city near Iguala.
About 15 of the students were already dead when they arrived and the rest were shot, according to the suspects.
Jesus Murillo said the bodies were then burned with petrol, tires, firewood and plastic in an inferno that lasted for 14 hours.
A total of 43 students went missing after clashing with police on September 26 in the town of Iguala
“The fire lasted from midnight to 2PM the next day. The criminals could not handle the bodies (for three hours) due to the heat,” he said.
He said that the suspects then crushed the remains, stuffed them into bags and tossed them in a river.
Jesus Murillo showed videos of investigators combing through small pieces of burned remains that were found in black plastic bags.
The suspects said they were not sure how many students they had taken but one said there were more than 40, Jesus Murillo added.
“The high level of degradation caused by the fire in the remains we found make it very difficult to extract the DNA that will allow an identification,” he added.
However, relatives of the missing remained skeptical. The families have been highly critical of the investigation into the students’ disappearance.
The case has shocked Mexico. Thousands have staged protests over what they say is collusion between officials and organized crime, along with government inaction.
President Enrique Pena Nieto has faced widespread criticism and on November 7 he vowed to hunt down all those responsible for the “horrible crime”.
The students from a teacher training college in Ayotzinapa, in Guerrero state, had travelled to nearby Iguala to protest against what they said were discriminatory hiring practices, and to collect funds for their college.
They went missing after clashes with the police.
Six people were also killed after police opened fire and witnesses described seeing the students being bundled into police cars.
More than 70 people have been arrested in connection with the disappearances, including the Mayor of Iguala, Jose Luis Abarca, and his wife, Maria de los Angeles Pineda, who were detained in Mexico City on November 4.
Mexican officials accused Jose Luis Abarca of ordering police to confront the students to prevent them from disrupting a public speech given by Maria de los Angeles Pineda.
The fugitive mayor of the Mexican town of Iguala, where 43 students went missing in September, has been arrested, officials announce.
Jose Luis Abarca was detained by federal police officers in the capital, Mexico City, a police spokesman said.
Mexican officials have accused Jose Luis Abarca of ordering police to confront the students on the day of their disappearance on September 26.
Eyewitnesses described seeing them being bundled into police cars.
Federal police spokesman Jose Ramon Salinas confirmed the arrest of Jose Luis Abarca and his wife Maria de los Angeles Pineda on Twitter.
Mexican officials had issued an arrest warrant for Jose Luis Abarca and Maria de los Angeles Pineda after Iguala police officers said they had received an order from the mayor to intercept the students.
The officers said they had been told to stop the students from interrupting a speech given by Maria de los Angeles Pineda in Iguala on that day.
The students, from a nearby teacher training college, had travelled to Iguala to raise funds and protest.
They have not been seen since. A search has uncovered a series of mass graves in the area, but initial tests suggested they were not those of the students.
Iguala Mayor Jose Luis Abarca and his wife Maria de los Angeles Pineda were detained by federal police officers in Mexico City
Since then, more bodies have been uncovered and officials have cast doubt on the accuracy of the initial tests.
More forensic tests are currently being carried out.
Jose Luis Abarca and Maria de los Angeles Pineda were arrested in a flat they had rented in Mexico City, media reports said.
They did not resist the arrest.
They have been taken for questioning. Officials hope they will be able to shed light on the whereabouts of the students.
The events of September 26 have shocked Mexicans and have led to mass protests demanding that the authorities do more to find the missing students.
The 43 were part of a larger group which had gone to Iguala to protest against what they said were discriminatory hiring practices.
The students all attended a teacher training college in Ayotzinapa with a history of left-wing activism, and their presence in Iguala raised alarm bells with the local authorities.
When the students boarded busses to return to their college, they were stopped by police – allegedly on the orders of Mayor Jose Luis Abarca.
The officers opened fire and killed three students and three people in nearby vehicles.
They stopped one busload of students trying to flee and took them to a local police station.
According to police officers detained as part of the investigation, they then handed the students over to a local drugs gang.
The gang’s leader, who has also been arrested, says he ordered the students be “made to disappear”, after having been told they belonged to a rival gang.
However, he did not specify further what happened to them.
The gang leader also accused Maria de los Angeles Pineda of being “the main operator of criminal activities in Iguala”.
The relatives of the missing students said on November 3 that “no progress” had been made in the search for the 43 and expressed their anger over the slow pace of the investigation.
The governor of the state of Guerrero, where Iguala is located, resigned last month over the disappearances.