That was the case for Josue, who was robbed by local criminals as he hiked the 40-mile stretch of remote highway between a Guatemala border city, El Ceibo, and Tenosique, a southern Mexican city. The thieves slipped out of the nearby ranch land and stripped him of his possessions, even taking his sneakers and leaving him with one of the robbers’ decrepit, fungus-covered pair. According to prosecutors in the southernmost states of Chiapas and Tabasco, these robberies and assaults are fairly common. Women are also singled out for other forms of violence, with Doctors Without Borders reporting that one-third of female migrants suffer sexual abuse while in Mexico.

To advance north, the poorest Central Americans climb aboard Mexico’s train cars (nicknamed “La Bestia,” or the Beast) and ride exposed through rain, heat and frigid wind, and with the constant fear of slipping off the sides. They also travel on high alert for the gang members or train security guards who sometimes board the trains to extort or rob the riders. Given these extreme risks — along with Mexican officials’ 2014 crackdown on migrants riding the train through the Southern Border Plan (Programa Frontera Sur) — only 12 percent of Central American migrants in 2017 reported to Colegio de la Frontera Norte researchers that they had taken the trains at any point in their journey.

Migrants with a little more money use private cars, buses or trailers and move along Mexico’s major north-south highways; they pass through the Mexican migration checkpoints by passing as locals or paying off corrupt officials. Some avoid the checkpoints altogether and hike around them. Traveling in vehicles is generally safer for migrants, but there may still be hardships from the varying quality of food, abysmal sleeping arrangements or mistreatment from their guides or fellow migrants.

At the United States border, patrol agents and a range of radars, sensors and other technology seek to block the migrants’ irregular crossing into the United States. In response, some Central Americans may attempt to cross in the remote areas in the vast California or Arizona deserts or near the border city of Ciudad Juárez. Others ask for asylum at ports of entry. But most travel up Mexico’s Gulf Coast to reach Reynosa, Tamaulipas. This city shares a border with McAllen, Tex., within the southern Rio Grande Valley. In fiscal 2017, the United States Border Patrol reported that it apprehended two-thirds of all irregular Central American migrants (104,305 in total) in this 320-mile section of the border.

On the Mexico side of the border near Reynosa, drug trafficking organizations, particularly the Gulf Cartel and the splinter groups of the Zetas, control the territory and the smuggling routes and act as unofficial tax agents. These groups offer the Central American migrants’ final security challenge and engage in their signature crime, kidnapping. Their presence gives this area the nefarious distinction of having the highest number of migrant kidnappings. Since 2011, data from Mexico’s National Migration Institute has documented 1,034 kidnapping victims in Tamaulipas — 75 percent of all migrant kidnapping victims in the country. Women and minors each account for more than a quarter of the victims.

But official numbers barely scratch the surface of the crimes committed against migrants in Mexico. Central Americans rarely report the crimes to Mexican authorities because of a lack of trust, fear of repercussions or limited knowledge of the country’s justice system. Josue is a good example. He was able to escape his captors after the Federal Police intercepted a car that was taking him to a second safe house, but he decided not to report the kidnapping given concerns over his safety.

When migrants do report these crimes, few are ever investigated or prosecuted. In July 2017, the Washington Office on Latin America reported that only 1 percent of crimes against migrants in Mexico ever reach a conviction.