Time is running out for the Trump administration to reunite thousands of immigrant children separated from their parents before a court-ordered July 26 deadline.

But nearly 500 of those parents have likely already been deported and are back in their home countries — and it's unclear how the government will find them.

Lawyers and rights groups say finding those parents is like searching for "a needle in a haystack."

The Trump administration is just two days away from its July 26 deadline to reunite thousands of immigrant children it split from their parents under the "zero tolerance" policy.

But the complexity and pace of the reunifications so far have sparked concerns that some of those separations could end up being permanent.

Government attorneys said in court documents on Monday that 463 parents of children between the ages of 5 and 17 were "not in U.S." and "under review," indicating that they may have been deported. The development raises new questions on how the government will reunite those parents with their children, or if reunification will even be possible.

Many of those parents were likely sent back to violence- and poverty-stricken Central American countries, and they've been difficult to track down now that they're back in their home countries, according to lawyers and rights groups.

In some cases, even their own lawyers aren't sure where they've gone.

Some parents may not have had a home left to return to, and others may have been too afraid to go back to the neighborhoods they fled. Some may not even have a reliable way of communicating with the government about their child still in the United States.

Robert Lopez, spokesman for the Texas Civil Rights Project, told Business Insider the group is working on six cases involving deported parents whose children remain in the US, and they haven't been able to find the parents yet.

"I can see a situation where a parent is unable to ever contact their child again because something happened to them in their home country," Lopez said.

'I don't think the government is reaching out'

In addition to the 463 deported parents, the Trump administration also deported 12 parents of children under the age of five.

Though the 103 younger children's reunifications were prioritized first — a federal judge ordered them to be completed by July 10 — the Trump administration failed to reunite the ones whose parents were deported by deadline.

It's unclear whether the government has made progress on those reunifications since, but the Homeland Security department said in a recent press release that the 12 deported parents it had identified for the youngest children "are being contacted."

Lopez said he's concerned about how the government and legal aid groups will contact those parents — for the Texas Civil Rights Project, the process was challenging enough just to confirm that those six parents they has identified had, in fact, been deported without their children.

Though TCRP lawyers briefly met those parents before they were prosecuted for illegally crossing the border, it wasn't until the lawyers later failed to track them down using the ICE detainee locator that they realized the parents may no longer be in the country.

When TCRP's law clerks called ICE to confirm the parents had been deported, they were often hung up on, Lopez said. He added that he wasn't sure if the hang-ups were intentional or unintentional.

Lopez said it's likely that TCRP is working on far more than just six cases involving deported parents — they just don't know it yet.

"We are fairly sure there are more deported parents that no one has learned of or talked about within our networks, within the grassroots organizations who are tracking this stuff," he said. "And I don't think the government is reaching out right now."

'A needle in a haystack'

A Honduran child plays at the Catholic Charities Humanitarian Respite Center after recently crossing the US-Mexico border with his father on June 21, 2018 in McAllen, Texas. Getty Images/Spencer Platt Nonprofits that work with immigrant children are used to encountering situations where a lone immigrant child must be matched with and sent back to family members in his or her home country — but not on this scale.

Emily Kephart, who works for the nonprofit Kids in Need of Defense, said even before the Trump administration implemented its "zero tolerance" policy that separated immigrant families en masse, KIND saw 40 family separation cases within the last year, 34 of which involved parents who were deported before their children.

"It was a slower pace. They were sort of trickling in each month, and certainly the zero-tolerance policy and the dynamic it created has changed things a little bit. But we've seen it happen, so I know what it looks like," she said. "But I'll also tell you, I don't know what it'll look like going forward."

Typically, when the government tries to deport a separated or unaccompanied child, a judge will grant them a voluntary departure order after their asylum claim is rejected or the child decides to go home, Kephart said. Then, Immigration and Customs Enforcement coordinates with the home country's consulate, and children fly home.

By that point, the government will have informed the home country's government of the time and date of the children's arrival flights. If they're from Central American countries, the governments have typically already set up reception centers that will have contacted the children's families, screened them for safety risks, and asked them to come greet the children.

Kephart said her best guess is that the Trump administration will use that system to repatriate the children whose parents have been deported — but there are a few key differences between the unaccompanied children Kephart usually works with and the separated children the Trump administration is working with now.

"Normally, in my project, I see kids who are returning to relative safety. It may be extreme poverty and difficult situations, but not imminent danger, because they've gone through this screening process," she said. "But in this situation with the family separations, both on the parents' side and the child's side, they're being driven by this extra stress factor of, 'I just want to be back with my family.' They might actually be returning to situations where they're not safe."

Just tracking down the separated children's deported parents has been an exercise in "determination and creativity and tenacity," Kephart said.

Putting out the call in their home countries

A child from Honduras is brought to the United States Immigration and Customs Enforcement office in Grand Rapids, Michigan on July 10, 2018. Associated Press/Paul Sancya

Nonprofits like KIND have been linking up with their counterparts in countries like Guatemala, El Salvador, and Honduras to find the separated children's parents.

But the only surefire way of getting ahold of a separated parent is if the parent approaches the organizations or their local government for help first.

"The families are reaching out to whoever they can, and then the information is sort of trickling back to us, because we are a known entity in the communities," Kephart said. "But if someone calls me and says, 'I have Jane Doe in this shelter, can you help me find her parent?' That's like a needle in a haystack."

Kephart said she's optimistic that the majority of separated families will eventually be reunited, but it won't be easy.

And she's uncertain the families will have had access to due process for their asylum claims, or that they'll recover easily from the trauma of their separation.

"I can't speak as to what's actually going to happen, but I know it's going to be complicated. Really complicated," she said.