Thousands marched through Mexico City this Saturday in a solemn and spirited commemoration of the first anniversary of the disappearance of 43 student teachers that continues to spark mass indignation one year on.
"Today we can say that we are not alone," said Felipe de la Cruz, spokesman for the parents of the missing students who headed the march. "We are going to walk together and we are going to be so organized that there is no army that can stop us."
People lining the capital's emblematic Reforma Avenue applauded as the parents marched by, leading the demonstration towards a rally in the massive Zócalo plaza in the center of the city as a persistent drizzle developed into steady rain.
The crowds in the march walked in silence for long periods, punctuated by energetic chants of the numbers from "One" to "Forty Three," ending with a cry of "Justice." Many held modified versions of the Mexican flag with the colors changed to black. Several women walked with stickers on their bodies that said "We Are Missing 43."
A year since the disappearance of the students from the Ayotzinapa Normal School, after buses they were travelling in were attacked by municipal police in the city of Iguala, Guerrero, the parents' expressions of their pain mixed with anger directed at the government's clumsy handling of the atrocity.
"I will never get tired of marching for my son, in this year of impunity," said Joaquina García, whose son is among the missing. "The government has to return him."
The parents reject the government investigation's conclusion, dating from November, that the 43 missing students were almost certainly massacred and incinerated at a rubbish dump outside the neighboring town of Cocula by members of a local drug gang called Guerreros Unidos, which had taken control of the local police. Their conviction that the government is trying to cover up what really happened was further strengthened by a report released earlier this month written by a group of independent experts assembled by the Inter-American Commission on Human Rights who said they had found no physical evidence to support the official version.
Related: Ayotzinapa: A Timeline of the Mass Disappearance That Has Shaken Mexico
So far only one of the students has been clearly identified among bone fragments found in a river that the government said came from the dump. A possible match also exists with a second student.
"I thought that I was ignorant because I never studied," Emiliano Navarrete told the rally at the end of Saturday's protest. "Now I realize that the ignorance lies in the government that attacks us."
The march was punctuated by sporadic calls on President Enrique Peña Nieto to resign. The president's popularity has plunged over the last year. A string of corruption scandals and a struggling economy have also damaged his image at home and abroad. One group of protesters carried a piñata of the president.
Peña Nieto has repeatedly sought to contain the political fallout from the disappearance of the Ayotzinapa students to local level police and institutions. He has avoided mentioning evidence that the federal police and the army were monitoring the students' movements in Iguala and failed to intervene when they were attacked. He has also ignored allegations that federal forces were directly involved. The attacks also killed three students, a youth soccer player, a bus driver and a female bystander. Another student was shot in the head and remains in a coma.
President Peña Nieto, who is in New York attending the United Nations General Assembly, marked the anniversary with several tweets pledging future advances in the investigation that he has promised will take into account the findings of the Inter-American Commission's report.
"One year on, I reiterate the commitment of the Mexican government to truth and justice," he wrote in one tweet. "We will continue to advance in the investigation, and ensure that the guilty are brought before the law," he said in another.
As he waited for the march to arrive at the Angel of Independence monument, Mexico City teacher Pedro Juárez underlined the protesters' deep skepticism of the government's sincerity.
"Over the past year the government has not responded [to the protest movement]," he said. "The government does not share the feelings of the people. This is the response of the people."
Saturday's march was not as big as some of the protests that shook Mexico during the first few months of public outrage sparked by the students' disappearance. It was, however, far larger than recent demonstrations that had dwindled to little more than the parents and their staunchest supporters.
"It gives you hope to see people protesting. It makes you dream about a change," said first year communications student Karime Nava. "Ayotzinapa is a shameful case for our country. It is something that could happen to anyone who dares to speak out."
More than 25,000 people have gone missing in Mexico since the country's drug wars began to intensify in 2007, according to official figures. President Peña Nieto promised to create a special prosecutor's office to investigate all of them at a meeting earlier this week with parents of the Ayotzinapa students. They rejected the idea as an effort to dilute attention from their children.
During the march Vidulfo Rosales, a lawyer from the human rights group Tlachinollan that has supported the parents from the start, nevertheless underlined the role of the Ayotzinapa case as a symbol for the wider phenomenon.
"This is not just a struggle for the 43 students. It is also for the 25,000 people disappeared in our country," he said. "If they [the government] thought that the movement would fade away and fragment, we say to them from here that we are still strong, and motivated to continue along this road without ever giving up."
Hans-Maximo Musielik, Daniel Hernandez, Gabriela Gorbea, and Jo Tuckman contributed to this report
Follow Melissa del Pozo on Twitter: @melissadps