She saw men and women packed into cages — “cage after cage after cage,” Sen. Elizabeth Warren (D-MA) wrote of her visit to a Border Patrol processing center in McAllen, Texas.

Warren recounted, in visceral detail, her June 24 visit to the processing center in McAllen and a US Immigration and Customs Enforcement (ICE) “family reunification and removal center” located in southern Texas in a pointed letter to Homeland Security Secretary Kirstjen Nielsen and Health and Human Services Secretary Alex Azar.

Warren is demanding answers from officials on their procedures for reuniting parents and children. She visited the facilities just a few days after President Donald Trump signed an executive order to end the separation of families at the border.

In her letter, she described people packed into cages with foil blankets, and the stories of migrants who were split apart from their children at the border, many of whom have been unable to track down their children. She noted officials working at the facilities were unable to answer questions or elaborate on policies.

“I was appalled by what I observed first hand, and I was shocked by the stories told by the people detained at these facilities,” Warren wrote.

I first visited the McAllen Central Processing Center in McAllen, Texas, which is operated by CPB. Inside the processing center, men and women were packed into cages — cage after cage after cage. Our group estimated that between forty and fifty men were being held in a cage that measured roughly ten feet by thirty feet. There was a wall a few feet high int eh back that separated a small urinal area from the rest of the cage. The men were cramped, lying side by side under foil blankets directly on a concrete floor. CBP officials insisted that no one was held for longer than 72 hours. But as I walked by the cages, I asked the migrants through the metal grates how long they had been there. They held up their fingers in response: four fingers, five fingers, two hands’ worth. Some told me they had been held for fourteen days. One man called out to me that he just wanted a shower — he said he’d gone six days without a shower or the opportunity to brush his teeth. Another man told me that his two children, aged 15 and 16, were being held separately in the other room.

Warren saw mothers with toddlers, girls, and boys, all in separate cages in another part of the facility.

Passing portable latrines, I walked up next to a cage where girls aged ten to fourteen were being held. I asked a group of about twenty of these children how long they had been there. Some said a day or two, others said five to ten days. I asked if they knew what was going to happen to them. They all shook their heads no. These children had nothing — no books, no toys, no games, and no sense of what their futures might look like.

Warren also visited a Port Isabel detention facility in Los Fresnos, Texas, which had been designated as the primary “family reunification and removal center.” Warren said there she only met parents who had been separated from their kids.

Warren recalled that she asked ICE officials about the whereabouts of children who had been separated from their parents, but the officials were unable to answer or give more details on the process of reunification. Of the nine mothers held at the facility whom Warren met, only one had spoken to her child.

A woman from Honduras who arrived at the processing center on June 12th had come across the border with her two girls, aged six and fourteen. At the border processing center, which she referred to as the “dog pound,” she said she witnessed a CBP officer telling a mother, “Give me your child, or I’ll have to chain you up.”

Another mother told Warren that a woman had asked the migrants to sign deportation papers; if they did so, they would be reunited with their kids. Vox’s Dara Lind reported that the administration is using this “reunification and removal center” to reunite families, only to deport them together — and at the expense of asylum claims.

Warren is asking DHS and HHS to clarify their process for family reunification, and account for their procedures to put parents in touch with their kids. “The ‘zero-tolerance’ policy that tore these families apart,” Warren wrote, “was implemented with no plan whatsoever on how to bring them back together again.”

Read Warren’s full letter to the Department of Homeland Security and Department of Health and Human Services below.