Last month a top Health and Human Services Department official testified that almost 1,500 migrant children are unaccounted for after being placed with sponsors by the department.

Why it matters: This comes as the administration is heightening crack down on migrants crossing the border, including the separation of families. Reports about the unaccounted minors have also raised concerns that they could be in the hands of human traffickers or being used as laborers by people who posed as relatives.

How we got here: Acting assistant secretary of the Department of Health and Human Services’ Administration for Children and Families Steven Wagner, last month told the Senate homeland security subcommittee that the agency learned of 1,475 missing kids after calling to check in with their sponsors.

Who are these children: They had crossed the southern border on their own, fleeing from gang violence and other social ills. There were 4,314 unaccompanied minors who crossed the border just last month and 26,000 since October.

Who are the sponsors: They’re usually parents or family members already residing in the U.S. who should also undergo background check. DHS told the Washington Post that about 85% of sponsors who receive custody of the minors are parents or close family members.

What the administration is saying: HHS officials said it's not the agency's legal responsibility to account for the children once released from its Office of Refugee Resettlement, per the Post. They also said sponsors might have intentionally declined to respond to inquires.