Obama administration has been warned of rise in child migrants since 2012

A team of researchers at the University of Texas at El Paso sent a 41-page report to the Department of Homeland Security (DHS) in August 2013 warning of the rise of unaccompanied minors from Central America crossing the southern border and questioning the federal government's capacity to handle the situation.

But Victor Manjarrez Jr., a former Border Patrol station chief who led the study, told The Washington Post that DHS viewed the surge in children as a "local problem" and didn't predict a broader crisis. Former government officials, outside experts and immigrant advocates all told the Post that the administration's reaction led to an inadequate response that has resulted in the huge surge seen in 2014.

"This trend was more like a hockey stick, going up and up and up," Muñoz told the Post. "Nobody could have predicted the scale of the increase we saw this year. The minute we saw it, we responded in an aggressive way."

But there were warnings as early as 2012, both from the first ladies of Mexico, Honduras and Guatemala who spoke at a conference in Washington on unaccompanied minors, and from Texas Gov. Rick Perry, who wrote a letter to Obama after a 90 percent increase in arrivals over the previous year. He warned the federal government would be "perpetuating the problem" by not moving quickly to repatriate Central American children and discourage others from making the dangerous journey.

The White House was also "directly involved" in efforts in early 2012 to open a temporary shelter at Lackland Air Force Base in San Antonio, Texas, to house the rising number of child arrivals, the Post reports.

"There were warning signs, operational folks raising red flags to high levels in terms of this being a potential issue," one former senior federal law enforcement official told the paper.

They also reported that lawmakers in Washington were hearing reports of the chaos and began increasing the budget of the Health and Human Services Office of Refugee Resettlement, which was responsible for sheltering and caring for the children after they were transferred over from Customs and Border Patrol.

Rep. Lucille Roybal-Allard, D-Calif., told the Post that while Democrats were aware of the urgent problem, they feared that speaking out about the problem too much would make it too politically difficult for Congress to pass an immigration overhaul.

"That was always a concern of mine: How to address the issue in a way that did not detract from the need for comprehensive immigration reform," she said.