In the loading docks, children sat in a darkened auditorium watching the animated movie Moana.
Where there were once racks of clothes and aisles of appliances, there were now spotless dorm-style bedrooms with neatly made beds and Pokemon posters on the walls.
The back parking lots were now makeshift soccer fields and volleyball courts. The McDonald’s was now the cafeteria. All this made it difficult to visualise what the sprawling facility used to be - a former Walmart Supercenter.
The converted retail store at the southern tip of Texas has become the largest licensed migrant children’s shelter in the country - a warehouse for nearly 1,500 boys aged 10 to 17 who were caught illegally crossing the border.
The teeming, 250,000-square-foot facility is a model of border life in Trump-era America, part of a growing industry of detention centers and shelters as federal authorities scramble to comply with the president’s order to end “catch and release” of migrants illegally entering the country.
Now that children are often being separated from their parents, this facility has had to obtain a waiver from the state to expand its capacity.
Cots are being added to sleeping areas. The staff is expanding. But even that is not enough. Federal authorities are considering establishing tent cities on Army and Air Force bases, and have already transferred hundreds of immigrant detainees to temporary housing at federal prisons.
On Thursday, the Department of Health and Human Services announced that temporary tent housing would be set up near the border station in Tornillo, Texas, to house up to 360 youths.
That prompted an angry response from a Democratic state senator, José Rodríguez, who noted that temperatures could be expected to exceed 100 degrees at the site. “This is what totalitarians in the Middle East and elsewhere do,” he said in a statement.
The federal Office of Refugee Resettlement is now overseeing an estimated 100 shelters in 17 states, serving a population that has grown to more than 11,000 youths. One of the biggest concentrations is here near the border in South Texas, in the Rio Grande Valley, one of the poorest regions in the nation.
There are about 10 shelters in three Valley counties, the majority in the Cameron County cities of Brownsville, Harlingen and San Benito.
The shelters in and near Brownsville have become big business, employing hundreds of residents and bringing abandoned stores, schools and other buildings back to life in a county where the median household income is $34,578 and the percentage of those living below the federal poverty line is 29.1, far higher than the national poverty rate of 12.7 percent.
But they have also raised questions about federal oversight and management, and the invisibility under which many of them operate.
Numerous shelters that care for unaccompanied migrant youth in Texas have been cited by state child care facility regulators for dozens of violations in recent years, according to data from two of the state’s oversight agencies, the Texas Health and Human Services Commission and the Department of Family and Protective Services.
The majority of the violations were for minor infractions, including incomplete child records. But some were for more serious problems.
At least 13 deficiency citations have been filed against the shelter at the former Walmart in Brownsville, which seemingly overnight became a symbol of the housing scramble after a Democratic lawmaker, Senator Jeff Merkley of Oregon, showed up unannounced to take a tour but was turned away by police escort.
Mr Merkley’s attempt to gain entry this month, captured on Facebook Live by a member of his staff, put national attention on the shelter, which is run by a nonprofit group that contracts with a federal agency.
The shelters are part of the federal government’s attempt to accommodate a flood of young people who have been surging across the Southwest border over the past several years, often without an accompanying parent. Many of them are seeking asylum from gang violence or other troubles in Central America.
The number of children under detention has grown in recent weeks as the Trump administration has begun prosecuting migrants who cross the border illegally.
Previously, parents traveling with children were often quickly released with orders to appear later in court - a practice which members of the current administration say was providing a powerful incentive for migrants to take their children in tow and travel to the United States.
The number of families apprehended at the border has gone up nearly 600 percent compared with the spring of last year, the Homeland Security secretary, Kirstjen Nielsen, told Congress in May.
“Word is getting out,” she said.
But what happens to children in these federally sponsored shelters has had little public scrutiny.