Now nearly 20 months old, Mateo was returned to his family on Feb. 8 after a battle across borders, officialdom and languages. He was filthy and terrified of the dark, his mother said. Months later, the boy still screeches even as Caceres rocks him on her chest, sometimes until dawn.
The Salvadoran family's story of struggle in US immigration detention presaged what was to come: Trump's "zero tolerance" policy that led to more than 2,300 migrant children being separated from parents in recent weeks.
Caceres' quest to find her child foreshadows the long road ahead for many immigrant families after Trump reversed the separation policy and directed agencies to begin reuniting families this week.
Last year, Caceres, her husband Jose Demar Fuentes, and their children Mateo and five-year-old Andree, fled El Salvador where gangs had demanded protection money, and crossed Mexico in one of the regular 'caravans' of migrants that travel together for safety.
On Nov. 12, Fuentes sought asylum at the US-Mexican border, with Mateo in his arms, citing the gang threats. Caceres was due to follow a few days later with Andree.
But Caceres heard that US immigration officials had taken Mateo from Fuentes on Nov. 16, as Fuentes was being transferred to a San Diego detention center. Still in Tijuana, she began a frantic search for her son.
When she finally got Mateo back in February, "he looked like he hadn't been bathed in three months", said Caceres in a telephone interview with Reuters this week from Los Angeles.
"It was very hard to see the condition he was in. I don't want to imagine that mountain of children, how they care for them," she said, choking on tears.
The potential consequences of such separations include impacts on brain development and mental health, as well as persistent behavioral and academic problems, especially for under-fives, child development experts say.
That first night, Mateo was inconsolable as Caceres held him tight, whispering he was "with your mama," she said.
Caceres had finally located Mateo at a facility in Texas. The phone number for the facility she provided to Reuters is registered to International Educational Services Inc (IES).
A nonprofit, IES closed its centers in Texas in March after losing funding from the Office of Refugee Resettlement, according to local media reports. A spokeswoman for the Texas Health and Human Services Commission confirmed that the facilities were inactive.
That agency found various violations during its inspection of IES facilities, including improper administration of medication, according to the agency's website.
In a statement to local media, IES did not say why it shuttered the facilities. ORR did not immediately respond to request for comment. There was no answer at IES' listed phone number or from employees' emails. Texas HHS did not provide a reason for the closure.
Locating Mateo took Caceres a week of phone calls to similar institutions on numbers she was given after speaking to a hotline for immigrant parents separated from their children.
Caceres called some numbers 10 times to get an answer. One official said Mateo was not entered into the system at all.
For a time, it seemed her son did not exist in U.S. bureaucracy.
On the seventh day of calls, late in November, she got through to IES.
"Yes, he's here," the person at the end of the line said. "Are you the mother?"
Shaking with relief, she asked for information on Mateo's health, his mood, how he was being fed and how he was sleeping.
With help from a pro-bono lawyer, Caceres emailed the documents she had: Mateo's birth certificate, a hospital form with the baby's footprints and her Salvadoran identity card.
The director of the Texas facility demanded a DNA test. In the end parentage was established with the help of a representative from the Salvadoran consulate in Texas who certified the documents, Caceres said.
It then took time to convince IES to let her talk to Mateo and then only by sending a five-minute video of herself to the facility. Over the phone, she listened to Mateo cry as he was shown the video, unable to locate the source of her voice.
"He thought she was there to pick him up," her attorney Erika Pinheiro said. "He became very distraught after the call."
Officials at the center told Caceres they had no knowledge of her case nor how her son came to them. Immigration authorities just sent them the babies, they said, according to Caceres.
Caceres could not fly to fetch her son herself because of limitations on her movements, tracked by an ankle bracelet after she crossed the US border with Andree and sought asylum. She was staying with relatives in Los Angeles.
At one point she was asked, she and her attorney said, to pay $2,000 so an official could deliver Mateo from Texas. Pinheiro said the ORR specialist on the case ultimately agreed to waive the fee.
Back home, Fuentes, 30, and Caceres, 29, ran a shop selling artisan shoes. Like many small business owners, they were forced to pay a weekly "war tax" to Mara Salvatrucha, MS-13, one of two brutal gangs with fiefdoms across the country.
When the tax doubled from one week to the next, to $100, they could no longer afford to pay, Caceres said. But missing payment, she said, meant death. The family fled.
For reasons that are unclear, US immigration officials pulled Mateo from Fuentes' clutch as he was being transferred to San Diego's Otay Mesa detention center, along with the children of three other fathers. He was not told where the baby was sent.
A Customs and Border Protection official told Reuters this week the agency determined he and his minor son were citizens of El Salvador with no legal status to enter the United States, and handed them to U.S. Immigration and Customs Enforcement (ICE).
At the time, an ICE spokeswoman released a statement saying Fuentes did not have documents to verify he was the father and the child was too young to answer officers' questions.
Pinheiro and other advocates say Fuentes' Salvadoran identity documents and Mateo's birth certificate were evidence of their family connection.
Fuentes sought asylum alone with Mateo because the boy was sick after their journey from Central America, much of it undertaken on the open top of a freight train, and they wanted to get to the United States to seek treatment, Caceres said.
Fuentes, trained as a journalist, still remains detained in Otay Mesa, denied parole and family visits, according to Caceres and Pinheiro.
"It's difficult for me to take in that I am a risk of flight when I handed myself in and asked for asylum," he wrote in an anguished letter to Otay Mesa authorities seen by Reuters.
"I came to find security for my family and what I obtained was separation from my son, who was one year and two months old."
Mateo can now say "pa" and "ma," and when he explodes into violent crying, the only way Caceres finds to soothe him is with those words as she rocks him.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)