A few days later, I arrive in El Paso and cross into Juárez to meet Claudia, a young deportee originally from this dangerous town. The violence of the drug war hangs over everything along the border, and nowhere more than Juárez. For more than a decade, this city of 1.5 million residents was the epicenter of drug violence. More than 9,000 people were killed in the city between 2007 and 2011, and it's been plagued by scores of brutal rapes and murders of young women since the 1990s. We pile into her battered early 1990s station wagon — along with her son, daughter, and a friend who will translate — and head to the business strip of Juárez.

Today, while most of the city may resemble the backdrop of any number of B-movie Westerns set in a dusty Mexican border town, Juárez's business district is gleaming: Tall glass buildings branded with the names of American multinational companies rise above the streets, and well-appointed hotels cater to the needs of foreigners in town to check on their investments in the local maquiladoras. There's even a Wendy's and a fancy mall.

Over coffee, the mother of three tells me her story. After her mother died, Claudia, then 16, moved to the U.S. using a "shopping visa," which allows Mexicans living along the border to make day trips into the U.S. Living in Denver, she worked with an aunt who ran a food truck catering to construction jobs. She had two boys while living in the States, and made regular trips to and from Juárez to visit family and check on the family home. But in 2010, things changed as she was waiting to cross back into the U.S. after a visit to Juárez.

"They took away my visa," she says. "When I was living in Colorado, working selling food at the construction sites, I was given a ticket for not having a proper permit. And that appeared in the system [because] I had a court appearance and had failed to go. I was here alone, with the kids, and now pregnant again, it was a difficult situation. The only thing I knew how to do was nails and cook meals."

As the violence escalated in the 2000s and the city's economy collapsed, hundreds of wealthy Juárez citizens moved across the Rio Grande into El Paso, while untold numbers of other residents began crossing the border illegally on a nightly basis. Claudia decided to try to move back to the U.S. as well.

The border between El Paso and Juárez is, at best, porous: Despite miles of fencing, steel walls, and the constant presence of the border patrol, each night untold numbers of Mexican migrants literally run across the shallow Rio Grande and disappear into the city's sprawling neighborhoods. Claudia tried this route several times, but being pregnant made it difficult to run, and after several near misses decided to give up on the overland route.

Desperate, she contacted a coyote who "told me we could try to cross through a 'tunnel' and that I would have to walk 15 minutes and there wouldn't be any problem." The coyotes took Claudia to the border in a group of 20 migrants. Once they entered the tunnels, they would be locked in, making turning around impossible. And the "walk" quickly turned into crawling as the migrants navigated tight sewage pipes, slowly making their way in the pitch black further under the city. It was cramped for everyone, but at six months pregnant, the pipes closed in tight around her.

"I had to keep going. There was no light, there was water with chemicals, who knows what kind, it made the skin burn. We had to cross hunched over, crawling — I had to be careful because of my tummy … I got cut and scratched by broken glass, there were rats, there were cockroaches, there were all kinds of animals in the sewers," she says, pointing out scars on her hands and arms that are still visible.

Halfway through the crossing, a diabetic man with high blood pressure in front of Claudia collapsed. Unable to turn around, Claudia desperately began pushing his unconscious body in the dark.

"My hands were bleeding, my knees, I started having contractions, I started feeling weak. I couldn't push him forward anymore and asked the guy behind me to help. Because the tunnel was small, only one person could crawl through at a time, the guy behind me said that either he would cross over me, or we will stay here and die. There wasn't a lot of oxygen. He asked me to rub mud over my body so he can slide over, that he might be crushing me and the baby, that maybe the baby would come out, but that if he didn't do this we would all die."

Eventually, the two were able to get the man's body a mere five meters through the tunnel before they came to the exit. Bruised, bleeding, and suffering from premature labor contractions, Claudia emerged from the sewer into the El Paso night to find herself in a dark alley. While the other migrants scrambled to hide in dumpsters until their ride could arrive, she was in no shape to climb the metal bins, and collapsed in a dark corner, where border agents found her a few minutes later.

"The patrol asked me to get up, but I couldn't, and he noticed I was bleeding [from the contractions] so he called an ambulance in El Paso and took me to Las Palmas Hospital–Medical Center."

At the hospital, doctors stabilized Claudia and stopped her contractions, and bound fractures in both her wrists and one elbow before sending her to the local jail. "Once they took me to the cell, there were others there, around eight women, and they offered me food, coffee, they were really nice to me. But I didn't want to eat anything, I was worried, and worried for my kids I had left with my dad."

And while at the hospital doctors had put antibiotic cream on the cuts and rat bites, they hadn't done a thorough job of cleaning them. "After talking to the other girls there, one of them noticed that [my] arm was beyond red, it was more like black from the infection. I couldn't stand the pain, it was swollen. She said, 'We have to take [the bandage] off because if it gets worse you can get gangrene.'"

The woman, a nurse from Mexico, said that they had to go to the jail infirmary and steal whatever bandages and medicines they could to treat her wounds. "I took gauze and antibiotic cream … we were not allowed to take medications back to the cell, they could only be used at the infirmary, but I took some back anyway." The nurse and some of the other women in the cell took Claudia into the showers and began scrubbing her wounds. After a month in jail, Claudia was deported back to Juárez.

Though murder rates in Juárez have dropped off significantly in the last several years as the Sinaloa cartel has taken control of much of the border and a new government in Mexico City has taken power, the damage has been done. Unlike other border towns where entrepreneurial locals sell trinkets, sombreros, and pictures with donkeys painted as zebras, Juárez's main downtown crossing is desolate, aside from a handful of men touting local pharmacies' Viagra prices. The violence has become so bad, even those seeking out cheap or illegal sex have long stopped coming to Juárez, leaving only the Mexican pharmacies to draw El Paso residents looking for cheap prescription drugs across the heavily militarized border.

And the collapse in the city's murder rate after 2011 may be little more than a breather: Martin Orquiz, a reporter with the newspaper El Diario who has covered crime and corruption for two decades, warned the violence will return. "It is going to be waves. Up and down, up and down. Because there are many bad people here, and their way of life is to take advantage of the rest of us," he says.

The situation for deportees along the border isn't likely to change anytime soon. Short of a dramatic upswing in the Mexican economy or the U.S. abandoning the efforts to control immigration — neither of which are likely to occur — deportations will continue. Although the U.S. has begun deporting some Mexicans to their home states, reducing the number of deportees in border cities, the flights are expensive, sporadic, and represent only a small part of the deported population.

Even if Congress passes comprehensive immigration reform providing citizenship to the millions of undocumented immigrants already in the U.S., that would be only a temporary fix. The sheer size of the border makes an impregnable border impossible, and the determination of migrants to enter the country at any cost ensures a steady flow of undocumented people in the future.

Claudia says that while she would like to be back in the U.S., she's not going to try crossing again, even if it means living in constant fear. She was attacked in broad daylight recently. "I would love to be there [in the U.S.] because of the kids," she says, corralling her son Nathan and daughter Valentina, who are playing among the coffee shop's tables, oblivious to the difficulties and danger all around them.

I ask her if she's nervous about raising them here. "Nervous? Yes," she says, stroking Valentina's hair. "I am afraid to be here because of my kids, because of all that has happened, because I am alone. I am afraid to be here. But I have no other options. I have no one else."