A Honduran woman named Esmeralda Pérez and her nine-year-old son, Jefferson, had just crossed the U.S. border when they were arrested, outside El Paso, on May 26th. “The agents came up to us, and my son said to me, ‘Mom, I’m scared,’ ” Pérez told me. “I said to him, ‘Don’t worry, these people aren’t going to hurt us.’ ” Pérez showed the agents her I.D. and her son’s birth certificate, and said that they were fleeing persecution. They were taken to a Border Patrol station, where they spent the night. The next day, around noon, an agent walked into their cell. “Come with me and bring me your kid,” he told Pérez. “The agent said he was going to take my son because I needed to pay a penalty and go to jail,” Pérez said. “But he didn’t tell me where they were taking him.” She hasn’t seen or spoken to her son since.

In the past month and a half, the Trump Administration has separated at least twenty-five hundred children from their parents at the U.S.-Mexico border, under a new zero-tolerance policy—without instituting a plan or protocol for how to reunite them. On Wednesday, the President signed an executive order that he claimed would halt the separations, but it made no mention of the families who had already been split up. They have been left in limbo. Some parents have already been deported, while their children remain in the U.S. Others are stuck in immigration detention, and, although they know where their children are, they cannot reach them. Pérez is in a third category. She’s still in criminal custody—she hasn’t had a chance to make her full asylum claim—and she’s not even sure where her son is.

On Wednesday morning, I visited Pérez at the Otero County Prison, a privately run facility in Chaparral, New Mexico, thirty miles north of El Paso. Pérez faces criminal charges for attempting to reënter the U.S. illegally—she crossed the border once before, in 2016—and is in the custody of the United States Marshals Service. We spoke through a glass partition in a small room in the women’s wing of the facility. When I told her that I had some questions about her situation, she said, in blunt, clear Spanish, “Do you have answers for me, too, or just questions?”

Pérez cried as she described all the unanswered questions that she had about her son. Jefferson has asthma, the result of a respiratory infection that he contracted five years ago, in Honduras. Would it flare up now that he was in a new climate? He also has a congenital skin infection. “If he doesn’t wash right, it gets infected and he’ll become very sick,” Pérez said. “Who’s going to tell him how to wash it?” A few days ago, through a relative who lives in the U.S., she heard that her son might be in Michigan, at a shelter run by the Office of Refugee Resettlement, the federal organization in charge of handling unaccompanied immigrant children. “Can I believe that, that he’s really there?” she asked me. “Can I believe anything? How can my son know what’s happening? I don’t even know what’s happening.”

Pérez’s lawyer, a public defender from El Paso named Erik Hanshew, is representing her in her criminal case, and also trying to help her get information about her son. “The family-separation policy is changing the lawyer-client relationship,” he told me. “My clients don’t even care about beating the charge they’re facing. It makes it harder to represent them, because all they want is to be with their children. There can’t really be due process for a parent in a situation like this.”

The only way a parent can locate her child is through O.R.R., but contacting the office is nearly impossible from inside detention. Hanshew works with an investigator named Irma Whiteley, who has been calling case managers at O.R.R. Whiteley joined me at Otero, where she shared the names and numbers of O.R.R. social workers with their clients and took out cash from her wallet to put money on their phone cards. “Sometimes these clients don’t want to tell you if they were arrested with their child,” she told me. “They’re scared and they don’t trust anyone. You have to convince them you’re on their side.”

Whiteley introduced me to another of their clients, a Brazilian woman named Wesliane Souza, who had been separated from her thirteen-year-old son. Souza told me that there were fifty mothers in her wing at Otero who’d been separated from their children. “Few of them know where their kids are,” she said. “Mothers are going to be leaving this facility with psychological problems.”

A Crisis at the Border More coverage of the Trump Administration’s immigration policy from The New Yorker.

Souza and her son travelled to the U.S., she said, to flee an abusive partner. They were arrested in El Paso, on June 1st, and taken to a Border Patrol station. Two days later, Souza was sitting in a holding cell with other women when an agent came over to tell her that she had five minutes to say goodbye to her son. “I didn’t know what to say to my son because I didn’t know where he was going,” she told me, in Portuguese. “There were other mothers and children all around us, and everyone was crying.”

None of the agents explained to the mothers how they could locate their children. The staff at the county jail, where Souza and the others were soon transferred, didn’t have answers, either. After four days, Souza was allowed to make a phone call. “I didn’t have any money to call anybody, so I called a cousin of mine in the U.S. who could accept the charges,” she said. “I asked her to help me find my son. It was easier for me to talk to her, on the outside, than it was for me to talk to my own son, who’s also a prisoner.” Her cousin eventually contacted O.R.R., and a social worker there confirmed that Souza’s son was safe. On June 16th, Souza’s cousin and son managed to speak briefly by phone.

Souza, however, has yet to speak to him, and she still does not know where he is. Her eyes were bloodshot from crying, and she rocked back and forth while we talked. During pauses in our conversation, a vacant look crept across her face, and she muttered to herself. On a table next to her were two books that she’d picked up from the prison chapel—the Bible and “Thirty-One Days of Prayer.”