Mexico border crossing
Mirna Sorlozano's daughter Glenda attempted to cross the border from Mexico to the US RONALDO SCHEMIDT/AFP/Getty

It was the most difficult day of her life. On the morning of 5 September 2010, Mirna Sorlozano stood in front of a cargo plane in San Salvador's airport, watching as soldiers unloaded a coffin. They said it contained the remains of her daughter, Glenda. The 23-year-old had been murdered alongside another 71 men and women in the Mexican town of San Fernando, in Tamaulipas, near the border with Texas, a few weeks earlier on 22 August.

Most were attempting to cross Mexico hoping to reach the US and find jobs that would help them support their relatives back home. But the journey is known to be one of the most dangerous in the world, with those travelling routinely facing abductions, torture and death.

Struggling to keep calm, Sorlozano took the coffin home where her relatives were waiting for her to decide, together, what to do next. Authorities warned her against opening it. They said she could get seriously ill and die. They advised her to bury it as quickly as possible. To move on. But she had serious doubts that the remains inside the grey metal box were those of her daughter.

"I needed to see it for myself so I opened the coffin and it was not her, it was not my daughter. There was nothing about her in there, it was not her clothes, her shoes, nothing. We just closed the box and sat there, not knowing what to do," Sorlozano said. The following day, she took the coffin to her local cemetery. She put a nameless plate above it and decided she would not stop until she found her daughter.

Plan to cross the border

Sorlozano last saw Glenda in the afternoon of 10 August 2010 as the young woman left her house in the department of La Libertad, El Salvador, carrying just a few things she could fit into a small rucksack. Glenda had a plan. She paid a smuggler to get her across the border with Mexico. Glenda would then have to find her way to the US.

"I told her not to go, that the route was too dangerous but she wanted to help us. I used to make only four US dollars a day selling coffee and bread and it wasn't enough to support us. She just wanted to help us," Sorlozano said.

It was the most difficult moment of my life. A woman hugged me and simply said: 'I'm sorry it is your daughter.'
- Mirna Sorlozano

Four days after leaving La Libertad, Glenda phoned her mother to tell her she was in Mexico. "Mum, I'm here and I'm OK. Please take care of yourself," she said, on a faint line. Sorlozano felt a sense of relief. Little did she know then that this brief conversation was the last she was going to have with her daughter. It wasn't until a week passed without receiving any news that she felt something had gone terribly wrong.

On 26 August, officials from the Salvadorian foreign ministry went to her house and told her they believed Glenda had been killed in a massacre in Mexico. A month later, they took her to the capital to take a DNA sample and a day later, confirmed the remains belonged to her daughter.

Sorlozano said: "It was the most difficult moment of my life. A woman hugged me and simply said: 'I'm sorry it is your daughter.' It was all very strange because a day after they took a DNA sample they confirmed she was my daughter. Even I know that is not possible."

Search for the truth

Sorlozano speaks about her eldest daughter as if Glenda was about to walk into the living room any minute. As long as she doesn't have solid proof that her daughter has been killed in San Fernando, she insists she is not dead. She spent the following years knocking on every possible door in the hope that she would find out what had happened to her daughter – and who the remains she had buried in her local cemetery belonged to.

In March 2014, Mexican authorities finally caved in. They agreed to meet Sorlozano in Mexico City and handed over an old cardboard box with personal belongings, including Glenda's identity card. They said that should be proof enough. She thought it was a cruel joke.

Sorlozano demanded the body she had buried in El Salvador be exhumed and that a new DNA be organized by independent forensics. Authorities have now agreed to run new tests, but no date has been set.

Fleeing poverty and violence

The route Glenda took to reach the US, in the hope of finding a better future for her and her family, is one of the most dangerous in the world. According to the International Organization for Migration, around 150,000 men, women and children make the journey every year, although civil society organisations claim the true figure is believed to be much higher. Most of them come from Central America, fleeing poverty and relentless violence.

Mexico President Peña Nieto
Mexico's President Enrique Pena Nieto has been criticised over a failure to investigate migrant abductions Reuters/Henry Romero

Along the way, hundreds fall prey to criminal gangs who abduct them for ransom, torture them, force women into sex work or murder them. Many have gone missing, never to be seen again while thousands have died in the US desert.

According to official figures from Mexico's National Institute of Migration, between 2013 and 2014, abductions of migrants increased tenfold, with 62 complaints registered in 2013 and 682 in 2014. Security forces have been known to work in collusion with the gangs.

Successive Mexican governments have chosen a "see no evil, hear no evil" approach to the horrors faced by people travelling through Mexico. The country's president, Enrique Peña Nieto, has miserably failed to ensure these brutal crimes are properly investigated.

In 2013, Mexico set up a forensic commission, made up by government representatives, independent forensic experts, human rights organisations and relatives of the missing migrants. Although this is a step in the right direction, investigations by the state are still slow and those responsible for the abductions, killings and disappearances rarely face justice.

Instead, the relatives of the missing – most of them families with scarce resources living in rural areas of El Salvador, Honduras and Nicaragua – are forced through a cruel procession of ministries and offices in Mexico and their own countries of origin, searching for answers that never come. Many have to pay for travel from their own pockets, the vast majority cannot even afford that.

Five years after Glenda's disappearance, Sorlozano agreed to name the blank tomb when she buried the box she was given. The plate now reads GMS, after Glenda's initials, but she insists not her daughter in there. She said: "In five years, I have not been able to lay a flower there. Until I have proof, I will keep looking for her."

Josefina Salomon is a news writer at Amnesty International in Mexico. Follow her on Twitter @josefinasalomon.