The internet was ablaze this weekend with reports that the US government had “lost” nearly 1,500 immigrant children inside the country. The news sparked outrage from advocates and activists, with some calling it a "crime against humanity”. But experts say the reality – while shocking – isn’t so simple.

The backlash started when disturbing quotes from a Health and Human Services (HHS) official starting circulating on social media last week. Steven Wagner, an acting assistant secretary at the agency, told Congress in April that HHS had lost track of 1,475 immigrant children they had placed with sponsors inside the US while their asylum cases were processed.

The admission sparked criticism online, spawning hundreds of tweets under the hashtag #WhereAreTheChildren.

“When I think about the 1500 lost children and those who are systematically separated from their mothers at the border, I come back to the same thought: If we can’t stop this in America we won’t stop it anywhere,” tweeted Texas Representative Joaquin Castro.

But the Trump administration shot back, with deputy press secretary Hogan Gidley calling the information “misreporting and fake news". So what really happened to those 1,475 children? The Independent spoke with experts to get the real story.

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Who are the children who were lost?

The kids were among the thousands of unaccompanied minors who arrived at the US border last year without a parent or guardian. Most came fleeing violence in Central American countries like Honduras and Guatemala, according to immigration attorney Greg Siskind. Many were sent across the border by their parents, in hopes that they would avoid the gang violence plaguing their countries.

Under US law, all unaccompanied children detained at the border are transferred to HHS care. The agency then places the children with sponsors, who are responsible for taking them to hearings and check-ins while their cases are processed.

HHS placed some 7,635 children with sponsors in the US between October 2017 and the end of the year, according to Mr Wagner's Senate testimony. When the agency conducted follow-up calls with the sponsors this year, they found that 6,075 of the children remained with their sponsors, 28 had run away, five had been removed from the country, and 52 had relocated to live with a non sponsor.

But the agency couldn’t account for the remaining 1,475 children, sparking headlines about the hundreds of unaccompanied minors HHS had lost.

10-year-old undocumented immigrant with cerebral palsy escorted by border patrol agents

Were all 1,475 children actually lost?

According to the Trump administration, no. HHS Deputy Secretary Eric Hargan put out a statement on Monday claiming that the children were not lost – their sponsors had just failed to answer check-up calls from the agency.

The agency makes these calls 30 days after the kids are placed in their new homes, out of an “abundance of concern for the welfare of the children,” Mr Wagner said in a press briefing. The children are often placed with sponsors who are undocumented immigrants themselves, he added, and are thus reluctant to answer calls from federal immigration enforcement.

“There's no reason to believe anything has happened to the kids,” Mr Wagner said, emphasising that the children are no longer in HHS custody once they are placed with sponsors.

Still, experts say this isn’t exactly a great look for the agency.

“I don't think anyone can justify a federal government agency that is supposed to keep tabs on kids in their trust and doesn't do so,” said David Leopold, an immigration attorney and former president of the American Immigration Lawyers Association.

“This is absolute agency incompetence,” he added. “They can’t keep track of the kids that are in their charge.”

People strike across America for A Day Without Immigrants Show all 16 1 /16 People strike across America for A Day Without Immigrants People strike across America for A Day Without Immigrants Demonstrators march during the "Day Without Immigrants" protest in Chicago, Illinois, February 16, 2017. Theopolis Waters/Reuters People strike across America for A Day Without Immigrants Demonstrators march during the "Day Without Immigrants" protest in Washington, DC, U.S., February 16, 2017. Aaron P. Bernstein/Reuters People strike across America for A Day Without Immigrants Protesters march in the streets outside the Texas State Capital on 'A Day Without Immigrants' February 16, 2017 in Austin, Texas. The crowd, which grew to well over a thousand participants, marched from the Austin City Hall to the Texas State Capital. Across the country hundreds of restaurants and eateries are closing for the day to protest President Trump's immigration policies and to highlight the contributions of immigrants to U.S. business and life. Drew Anthony Smith/Getty People strike across America for A Day Without Immigrants Protesters march in the streets outside the Texas State Capital on 'A Day Without Immigrants' February 16, 2017 in Austin, Texas. Drew Anthony Smith/Getty People strike across America for A Day Without Immigrants AUSTIN, TX - FEBRUARY 16: Protesters march in the streets outside the Texas State Capital on 'A Day Without Immigrants' February 16, 2017 in Austin, Texas. Drew Anthony Smith/Getty People strike across America for A Day Without Immigrants Demonstrators march during the "Day Without Immigrants" protest in Chicago, Illinois, February 16, 2017. Theopolis Waters/Reuters People strike across America for A Day Without Immigrants Demonstrators march during the "Day Without Immigrants" protest in Chicago, Illinois, February 16, 2017. Aaron P. Bernstein/Reuters People strike across America for A Day Without Immigrants Protesters march in the streets outside the Texas State Capital on 'A Day Without Immigrants' February 16, 2017 in Austin, Texas. The crowd, which grew to well over a thousand participants, marched from the Austin City Hall to the Texas State Capital. Across the country hundreds of restaurants and eateries are closing for the day to protest President Trump's immigration policies and to highlight the contributions of immigrants to U.S. business and life. Drew Anthony Smith/Getty People strike across America for A Day Without Immigrants Protesters march in the streets outside the Texas State Capital on 'A Day Without Immigrants' February 16, 2017 in Austin, Texas. Drew Anthony Smith/Getty People strike across America for A Day Without Immigrants Protesters march in the streets outside the Texas State Capital on 'A Day Without Immigrants' February 16, 2017 in Austin, Texas. Drew Anthony Smith/Getty People strike across America for A Day Without Immigrants Protesters march in the streets outside the Texas State Capital on 'A Day Without Immigrants' February 16, 2017 in Austin, Texas. Drew Anthony Smith/Getty People strike across America for A Day Without Immigrants Protesters march in the streets outside the Texas State Capital on 'A Day Without Immigrants' February 16, 2017 in Austin, Texas. Drew Anthony Smith/Getty People strike across America for A Day Without Immigrants Protesters march in the streets outside the Texas State Capital on 'A Day Without Immigrants' February 16, 2017 in Austin, Texas. Drew Anthony Smith/Getty People strike across America for A Day Without Immigrants Protesters march in the streets outside the Texas State Capital on 'A Day Without Immigrants' February 16, 2017 in Austin, Texas. The crowd, which grew to well over a thousand participants marched from the Austin City Hall to the Texas State Capital. Across the country hundreds of restaurants and eateries are closing for the day to protest President Trump's immigration policies and to highlight the contributions of immigrants to U.S. business and life. Drew Anthony Smith/Getty People strike across America for A Day Without Immigrants High school student Kathia Suarez holds up a sign as she protests with others outside the Grayson County courthouse in downtown Sherman, Texas, Thursday, Feb. 16, 2017. LM Otero/AP People strike across America for A Day Without Immigrants High school senior Vicky Sosa holds a sign outside the Grayson County courthouse in downtown Sherman, Texas, Thursday, Feb. 16, 2017. In an action called "A Day Without Immigrants," immigrants across the country are expected to stay home from school, work and close businesses to show how critical they are to the U.S. economy and way of life. LM Otero/AP

Is losing track of unaccompanied children a new problem?

Nope. According to experts, federal agencies have had trouble keeping tabs on these kids for some time. In fact, a 2016 inspector general report showed the federal government could reach only 84% of the children it placed with sponsors that year. More than 4,000 went unaccounted for.

“There have been a lot of complaints for the last couple years regarding the policies for kids that were coming across unaccompanied,” Mr Siskind told The Independent. “ So that hasn't changed that much since the Trump administration.”

Undocumented mother pledges to stay in New York City church until she earns reprieve from deportation

So why are people worked up about it now?

The news about the missing, unaccompanied children came at a bad time for the Trump administration: The Justice Department had just introduced its new, “zero tolerance” policy for families who cross the border illegally.

Under this new policy, debuted by Attorney General Jeff Sessions earlier this month, the Justice Department will prosecute all people caught immigrating illegally – regardless of whether they come with their children or not.

That means the government will have to separate these parents from their children while they face criminal charges. According to a Times analysis, more than 700 children have already been separated from adults claiming to be their parents since October.

The Trump administration has portrayed this policy as a common-sense means of cracking down in illegal immigration. "If you cross the border unlawfully, then we will prosecute you. It’s that simple,” Mr Sessions said at a press conference announcing the change.

But advocates say it is an unnecessarily harsh way of dealing with families fleeing unsafe conditions.

“[The Trump administration] is holding kids hostage to deter their parents from applying for asylum.” Mr Leopold said. “The idea is to deter people from coming and applying for protection. That is what authoritarian governments do.”