Later that day, in a pulpería across the road from the proc­essing center, I met a man named Bayron Cardona, who was a nervous wreck. He told me that he and his wife, Belky, had managed to cross the Rio Grande but were so intimidated by the Border Patrol presence in Texas that they decided to reverse course and were arrested while trying to get back to Mexico. Cardona and Belky were recent college graduates, still in their 20s, and last year they opened a computer-­repair shop in a building owned by Belky’s father. Their neighborhood was entirely under the control of the MS-13; members of the gang soon confronted Cardona, demanding an impuesto de guerra, or war tax. Impuestos de guerra are a common source of revenue for gangs throughout Honduras, and in Cardona and Belky’s area, every business paid. The amount the gang wanted far exceeded what Cardona could afford. When he failed to produce the money, the MS-13 threatened to kill him. Cardona and Belky went to the United States Embassy, applied for visas and were denied. Then they alerted the police — ‘‘our big error,’’ Cardona told me. That same day, after the couple closed their shop, someone slid a piece of paper under the metal shutter, a printed letter that read in part: ‘‘We know everything you do. We can kill you in your house or when you’re walking out of church. Call home to see what happens.’’ Cardona and Belky called Belky’s father, with whom they were living. Minutes earlier, he told them, two gunmen on motorcycles had driven by, shooting up the front porch with handguns.

A few weeks later, the couple climbed out of a small boat onto the banks of Texas. It was nighttime. There were ­bushes and then a road and then a fence and then a highway. Their coyote told them there was a gap in the fence that they should run for. Cardona and Belky hid in the bushes. White and green S.U.V.s drove up and down the road; officers patrolled on foot with dogs. Others rode on horseback. A helicopter appeared and hovered low. The rotor wash from its roaring blades flattened the tall grass and exposed the migrants hiding there.

Through the rest of the night and all the next day, Cardona and Belky watched one migrant after another make a dash, get caught. Sometimes, as the migrants ran, the dogs latched onto their pant legs. They were sleep-­deprived and dehydrated. Belky told Cardona she wanted to go back. They had Mexican visas; they would stay there or find another country to flee to. Cardona called the coyote and asked him to send a boat. He and Belky were down by the water, waiting to be collected, when a skiff motored up and flashed a spotlight on them. From the bank, an officer on horseback galloped over and told them not to move.

At a Border Patrol station in McAllen, Cardona and Belky were separated. Cardona was put in a cell with other men that was shockingly cold — a hielera, or icebox, as migrants call them. The men positioned a trash can under the ceiling vent to capture the frigid air; that way, huddled together, they could lie on the concrete floor. After two days, Cardona was transferred to a detention center, where he told an ICE official that he and his wife wanted to request asylum. The ICE official asked for Belky’s name. The next day, she was deported. The next week, so was Cardona. When I met him at the airport in San Pedro Sula, he had not seen Belky since their apprehension.

A few days later, I visited the couple at Belky’s father’s house. I met Cardona at a nearby restaurant so he could guide my driver through his neighborhood. He was anxious and fidgety. His father-­in-­law had paid half the war tax that they owed the MS-13 and told the gang that he and Belky were in America; Cardona didn’t know what would happen when the gang discovered they were back. He had changed the way he wore his hair, grown a beard and replaced his contacts with prescription glasses. We passed the building where his business used to be — it was now a barber shop. As we turned onto Cardona’s street, an MS-13 lookout, a teenager in a tank top, eyeballed us as we drove by. We rolled the windows down, a rule throughout Honduras when entering gang territory.

Climbing the front steps of his house, Cardona pointed out the divots in the walls where the bullets from the drive-by had struck. He went inside and returned with the death-threat letter that was slid into his shop. His father-­in-­law had found a nine-­millimeter shell, he told me, and probably still had it. I said that was fine, I didn’t need to see the shell. Belky came out, and we sat in the driveway between two huge barking dogs tethered to short chains. One had a painful-­looking knob protruding from its brow. Someone had hit it with a bat or a pipe, Cardona explained, while stealing their propane tanks.

Belky cried several times as she spoke. In McAllen, she told me, she was also put in a hielera. She was in it for three days, with many other women and young children, including a newborn and her mother, who had undergone a cesarean. The detainees were issued thin Mylar blankets for warmth; they all slept on the floor. There were no showers, and the only toilet had a camera aimed at it. Every 24 hours, each detainee was given two bologna sandwiches.