Some local agents in border towns complain the smugglers' techniques, gear and weapons are quickly outpacing theirs. Agents say hiding within the colonias, the Mexican-American neighborhoods along the Rio Grande where dilapidated trailers and poor farm workers reside, gang and cartel members are monitoring the whereabouts of law enforcement vehicles and agents.
"When I am doing ride-alongs with agents, you see people calling out our movements," says Rosendo Hinojosa, the chief border patrol agent for the Rio Grande sector. "Anytime they move narcotics or migrants, they have scouts. They are trying to defeat our defense."
While an immigrant journey may be arguably less predictable in Mexico with gang and cartel violence along the way, the terror doesn't end when immigrants arrive on the U.S. side of the border. Lupe Trevino, the Hidalgo County Sheriff, says he's overwhelmed by the migrant abuses that spill across the border.
Throughout the county, smugglers have established a network of stash houses, places where human smugglers keep immigrants once they've crossed the U.S.-Mexican border.
On a recent – and typical – Monday, the Hidalgo County Sheriff's tactical unit get out of their vehicles and surround a small, single-level apartment. The windows, covered in tinfoil, are locked. The door, dead-bolted. The officers feverishly began knocking and talking to the more than 30 individuals they suspect are inside, but their pleas are met with silence.
After 15 minutes, the officers abandon the exercise and drive away.
Stash houses are becoming a real problem in Hidalgo County. The resting places, sometimes torture chambers or exploitation centers, are hidden throughout the urban centers and rural outposts.
"It's almost like a warehouse. They treat these individuals like commodities," Trevino says. "The problem is that a lot of those [undocumented] folks are being victimized while they are there. The women are being assaulted and the men are robbed. We are averaging about three human stash houses a week now."
Sometimes, Trevino says the police will uncover 100 people in a three bedroom, single bathroom home. The smugglers feed occupants cold, canned food and crowd them onto old mattresses to sleep.
"The living conditions are deplorable. These places are not fit for human occupancy," Trevino says.
But the stash houses are just one horrifying leg of a more perilous journey.
When they leave the stash houses, migrants are stuffed like sardines in the back of semis, in the dashboards of pick up trucks, in the floorboards of Suburbans or in the trunks of small cars and driven up north. But border checkpoints as far as 60 miles north present another dangerous juncture.
In order to avoid the checkpoint, many smugglers will drop their migrants off on unmarked county roads, tell them the walk is just a mile or two, and send them on their way with a guide.
The walk is much longer than that, however. Many immigrants wind up walking 15 miles or more through the thick brush and along sand paths that feel heavy beneath their already weary legs.
If they cannot keep up, they are left behind to die of dehydration in the muggy fields. Sometimes, if they refuse to carry the 70-pound packs of marijuana for their smugglers, they are beaten. Women are raped and their undergarments are left hanging in the mesquite trees.
In Brooks County, Texas, the site of one of the checkpoints, 129 bodies were found last year. Already, 33 have been discovered this year.
"This area is the hot spot now," says Linda Vickers, a rancher who has had more than one run-in with the groups and bodies in the area.
The county buries the bodies in the local cemetery and places thin metal signs to mark the graves of the unknown.
"They are humans. That is what we all are," says Benny Martinez, the chief deputy at the Brooks County Sheriff's Department. "Who would blame them for wanting to get out of their country with crime as high as it is. They just want to feel comfortable. They just want to be looked at as human beings."