Migrants from Honduras, Nicaragua, El Salvador and Guatemala who want to reach the United States first have to travel through Mexico, where their path is long and hard, and too often becomes a deadly.
The mostly young Central American men and women who make it over Mexico's southern border usually still have most of the trip ahead of them. The border crossings in Tapachula, Chiapas, and in Chetumal, Quintana Roo, are the least of their problems.
It is after the southern border that their ordeal really begins. There are gangs of young thugs, often in the service of major drug cartels, who attack and rob them, rape the women and sometimes even kill them.
In a report issued in April, the human-rights organization Amnesty International charged Mexico with failing to protect migrants passing through the country from being preyed on by criminals and corrupt officials alike. The group said that organized crime in Mexico was expanding its reach to victimize Central American migrants.
"Their vulnerability makes them targets for kidnapping, human trafficking and extortion," Amnesty said.
Even when they are not directly involved, police often look the other away to cash in.
Until recently, the primary exploitation of migrants consisted of charging them to get them across Mexico's northern border into the United States. Recent events, including this week's massacre of 72 migrants at a ranch in the northern Mexican state of Tamaulipas, make it clear that conditions have changed for the worse.
The drug cartels increasingly try to get these impoverished people to join their ranks: according to media reports, almost 10,000 Central American migrants were kidnapped in Mexico over six months in 2009. Their families are asked to pay large sums of money, and whoever cannot pay in cash is made to pay in labour. Those who are not willing to cooperate with the drug gangs are killed.
"You'll need to pay us somehow, blondie," kidnappers told the Salvadorian Marisolina.
The young woman, currently a protected witness of the public prosecution, had no relatives in the United States or El Salvador who could pay 3,000 dollars for her release, according to her own account, which was published Thursday in the Mexican daily El Universal.
Her tormentor, a man nicknamed El Perro (the dog), was in charge of kidnapping and extorting migrants. One day, in a drunken haze, El Perro told Marisolina that it was also his job to kill those migrants who could not pay up.
"He said: 'First I cut them up in little pieces so that they fit into the bins, and then I set them alight until there is nothing left of those bastards,'" the young woman quoted El Perro as having told her.
According to Marisolina, who was eventually released, the abducted migrants were guarded by so-called soldiers of the organization. These included the "Alfa," whom she often heard talking to police and migration officials, who tipped off the organization on approaching groups of migrants.
On Friday in Mexico City, the federal migration authority said that around 90,000 migrants from Central and South America were sent back to their home countries in 2009. Authorities estimate that a similar number made it to the United States through Mexico during the year.
The mainstream route takes these migrants from the state of Chiapas through Oaxaca and Veracruz to Tamaulipas on the US border.
According to these estimates, around 10,000 migrants are kidnapped every year by organizations such as Los Zetas, a notorious drug gang allegedly responsible for this week's massacre. The Mexican military says Los Zetas demand 2,000 to 40,000 dollars to free their captives.
Migrant tells of abductions in Mexico