A young boy peers from the Mexican side of the US-Mexico border fence in Anapra, Texas.
CNN  — 

Questions abound about the 1,475 immigrant children the US government has been unable to contact since they were released to sponsors in 2017 – not least of all, where are they?

In late April, a top official with the US Department of Health and Human Services told a Senate committee that the Office of Refugee Resettlement made follow-up calls to check on the unaccompanied minors 30 days after they were released to sponsors. But 1,475 of the calls went unreturned, HHS Acting Assistant Secretary Steven Wagner told the committee.

Around that time, the Department of Homeland Security’s handling of immigrant family separation at the US border had begun to receive intense media scrutiny. Wagner’s comments drew additional criticism to his department, including reports that HHS had “lost track” of the 1,475 children.

In late May, HHS responded in a stern statement, calling the assertion that the children are lost “completely false.” The statement further said that the calls were “not required” and “not done previously.”

“This is a classic example of the adage ‘No good deed goes unpunished,’” HHS Deputy Secretary Eric Hargan said in the statement.

The children are most likely with their sponsors, many of whom are relatives, Hargan said. And in many cases, those sponsors are undocumented and don’t want to return ORR’s follow-up calls, the agency surmised.

While the children’s whereabouts may be unknown for the time being, CNN obtained data from HHS that sheds light on who they are. Here’s what we know so far.

More than one-third of the children were sponsored by their mothers or fathers, according to HHS data obtained by CNN. Six percent were released to unrelated sponsors and the rest were placed with other relatives.

The data shows that for a majority of the children, their country of birth was Guatemala, followed by Honduras, El Salvador and Mexico. Other countries of birth included Nicaragua, India, Brazil, Bangladesh, Venezuela, Colombia, Ecuador, Haiti, Nepal, Romania and Vietnam.

The children’s ages ranged from less than one year old to 18 years old. Most of them, 40%, were 17 years old, and two of them were infants.